pci/quirks: Add quirk to reset nvgpu at boot for the Lenovo ThinkPad P50

Submitted by Lyude Paul on Feb. 12, 2019, 10:02 p.m.

Details

Message ID 20190212220230.1568-1-lyude@redhat.com
State New
Headers show
Series "pci/quirks: Add quirk to reset nvgpu at boot for the Lenovo ThinkPad P50" ( rev: 1 ) in Nouveau

Not browsing as part of any series.

Commit Message

Lyude Paul Feb. 12, 2019, 10:02 p.m.
On a very specific subset of ThinkPad P50 SKUs, particularly ones that
come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
seems to have a very nasty habit of not always resetting the secondary
Nvidia GPU between full reboots if the laptop is configured in Hybrid
Graphics mode. The reason for this happening is unknown, but the
following steps and possibly a good bit of patience will reproduce the
issue:

1. Boot up the laptop normally in Hybrid graphics mode
2. Make sure nouveau is loaded and that the GPU is awake
2. Allow the nvidia GPU to runtime suspend itself after being idle
3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
4. If nouveau loads up properly, reboot the machine again and go back to
step 2 until you reproduce the issue

This results in some very strange behavior: the GPU will
quite literally be left in exactly the same state it was in when the
previously booted kernel started the reboot. This has all sorts of bad
sideaffects: for starters, this completely breaks nouveau starting with a
mysterious EVO channel failure that happens well before we've actually
used the EVO channel for anything:

nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
00000002

Later on, this causes us to timeout trying to bring up the GR ctx:

------------[ cut here ]------------
nouveau 0000:01:00.0: timeout
WARNING: CPU: 0 PID: 12 at
drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
gf100_grctx_generate+0x7b2/0x850 [nouveau]
Modules linked in: nouveau mxm_wmi i915 crc32c_intel ttm i2c_algo_bit
serio_raw drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
xhci_pci drm xhci_hcd i2c_core wmi video
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.0.0-rc5Lyude-Test+ #29
Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET82W (1.55 )
12/18/2018
Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
RIP: 0010:gf100_grctx_generate+0x7b2/0x850 [nouveau]
Code: 85 d2 75 04 48 8b 57 10 48 89 95 28 ff ff ff e8 b4 37 0e e1 48 8b
95 28 ff ff ff 48 c7 c7 b1 97 57 a0 48 89 c6 e8 5a 38 c0 e0 <0f> 0b e9
b9 fd ff ff 48 8b 85 60 ff ff ff 48 8b 40 10 48 8b 78 10
RSP: 0018:ffffc900000b77f0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888871af8000 RCX: 0000000000000000
RDX: ffff88887f41dfe0 RSI: ffff88887f415698 RDI: ffff88887f415698
RBP: ffffc900000b78c8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888872118000
R13: 0000000000000000 R14: ffffffffa0551420 R15: ffffc900000b7818
FS:  0000000000000000(0000) GS:ffff88887f400000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005644d0556ca8 CR3: 0000000002214006 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 gf100_gr_init_ctxctl+0x27b/0x2d0 [nouveau]
 gf100_gr_init+0x5bd/0x5e0 [nouveau]
 gf100_gr_init_+0x61/0x70 [nouveau]
 nvkm_gr_init+0x1d/0x20 [nouveau]
 nvkm_engine_init+0xcb/0x210 [nouveau]
 nvkm_subdev_init+0xd6/0x230 [nouveau]
 nvkm_engine_ref.part.0+0x52/0x70 [nouveau]
 nvkm_engine_ref+0x13/0x20 [nouveau]
 nvkm_ioctl_new+0x12c/0x260 [nouveau]
 ? nvkm_fifo_chan_child_del+0xa0/0xa0 [nouveau]
 ? gf100_gr_dtor+0xe0/0xe0 [nouveau]
 nvkm_ioctl+0xe2/0x180 [nouveau]
 nvkm_client_ioctl+0x12/0x20 [nouveau]
 nvif_object_ioctl+0x47/0x50 [nouveau]
 nvif_object_init+0xc8/0x120 [nouveau]
 nvc0_fbcon_accel_init+0x5c/0x960 [nouveau]
 nouveau_fbcon_create+0x5a5/0x5d0 [nouveau]
 ? drm_setup_crtcs+0x27b/0xcb0 [drm_kms_helper]
 ? __lock_is_held+0x5e/0xa0
 __drm_fb_helper_initial_config_and_unlock+0x27c/0x520 [drm_kms_helper]
 drm_fb_helper_hotplug_event.part.29+0xae/0xc0 [drm_kms_helper]
 drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper]
 nouveau_fbcon_output_poll_changed+0xb8/0x110 [nouveau]
 drm_kms_helper_hotplug_event+0x2a/0x40 [drm_kms_helper]
 drm_dp_send_link_address+0x176/0x1c0 [drm_kms_helper]
 drm_dp_check_and_send_link_address+0xa0/0xb0 [drm_kms_helper]
 drm_dp_mst_link_probe_work+0xa4/0xc0 [drm_kms_helper]
 process_one_work+0x22f/0x5c0
 worker_thread+0x44/0x3a0
 kthread+0x12b/0x150
 ? wq_pool_ids_show+0x140/0x140
 ? kthread_create_on_node+0x60/0x60
 ret_from_fork+0x3a/0x50
irq event stamp: 22490
hardirqs last  enabled at (22489): [<ffffffff8113281d>]
console_unlock+0x44d/0x5f0
hardirqs last disabled at (22490): [<ffffffff81001c03>]
trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last  enabled at (22486): [<ffffffff81c00330>]
__do_softirq+0x330/0x44d
softirqs last disabled at (22479): [<ffffffff810c3105>]
irq_exit+0xe5/0xf0
WARNING: CPU: 0 PID: 12 at
drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
gf100_grctx_generate+0x7b2/0x850 [nouveau]
---[ end trace bf0976ed88b122a8 ]---
nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 0000000000008000 engine
00 [GR] client 15 [HUB/SCC_NB] reason c4 [] on channel -1 [0000000000
unknown]

From which the GPU never manages to recover. Booting without nouveau
loading causes issues as well, since the GPU starts sending spurious
interrupts that cause other device's IRQs to get disabled by the kernel:

irq 16: nobody cared (try booting with the "irqpoll" option)
…
handlers:
[<000000007faa9e99>] i801_isr [i2c_i801]
Disabling IRQ #16
…
serio: RMI4 PS/2 pass-through port at rmi4-00.fn03
i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.4: Transaction timeout
rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX
register (-110).
i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
i801_smbus 0000:00:1f.4: Transaction timeout
rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change enabled
interrupts!

Which in turn causes the touchpad and sometimes even other things to get
disabled.

Since the GPU staying on causes problems even without nouveau's
intervention, we can't fix this problem from nouveau itself. We have to
fix it as early as possible in the boot sequence in order to make sure
that the GPU is in a clean state before it has a chance to spam us with
interrupts and break things.

So to do this, we add a new pci quirk using
DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
at boot finishes. From there, we check to make sure that this is indeed
the specific P50 variant of this GPU. We also make sure that the GPU PCI
device is advertising NoReset- in order to prevent us from trying to
reset the GPU when the machine is in Dedicated graphics mode (where the
GPU being initialized by the BIOS is normal and expected). Finally, we
try mapping the MMIO space for the GPU which should only work if the GPU
is actually active in D0 mode. We can then read the magic 0x2240c
register on the GPU, which will have bit 1 set if the GPU's firmware has
already been posted during a previous boot. Once we've confirmed all of
this, we reset the PCI device and re-disable it - bringing the GPU back
into a healthy state.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: nouveau@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Ben Skeggs <skeggsb@gmail.com>
Cc: stable@vger.kernel.org
---
 drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

Patch hide | download patch | download mbox

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index b0a413f3f7ca..948492fda8bf 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5117,3 +5117,68 @@  SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
 SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
 SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
 SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
+
+/*
+ * On certain Lenovo Thinkpad P50 SKUs, specifically those with a Nvidia
+ * Quadro M1000M, the BIOS will occasionally make the mistake of not resetting
+ * the nvidia GPU between reboots if the system is configured to use hybrid
+ * graphics mode. This results in the GPU being left in whatever state it was
+ * in during the previous boot which causes spurious interrupts from the GPU,
+ * which in turn cause us to disable the wrong IRQs and end up breaking the
+ * touchpad. Unsurprisingly, this also completely breaks nouveau.
+ *
+ * Luckily, it seems a simple reset of the PCI device for the nvidia GPU
+ * manages to bring the GPU back into a clean state and fix all of these
+ * issues. Additionally since the GPU will report NoReset+ when the machine is
+ * configured in Dedicated display mode, we don't need to worry about
+ * accidentally resetting the GPU when it's supposed to already be
+ * initialized.
+ */
+static void
+quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
+{
+	void __iomem *map;
+	int ret;
+
+	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
+	    pdev->subsystem_device != 0x222e ||
+	    !pdev->reset_fn)
+		return;
+
+	/*
+	 * If we can't enable the device's mmio space, it's probably not even
+	 * initialized. This is fine, and means we can just skip the quirk
+	 * entirely.
+	 */
+	if (pci_enable_device_mem(pdev)) {
+		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
+		return;
+	}
+
+	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
+	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
+	if (!map) {
+		pci_err(pdev, "Can't map MMIO space, this is probably very bad\n");
+		goto out_disable;
+	}
+
+	/*
+	 * Be extra careful, and make sure that the GPU firmware is posted
+	 * before trying a reset
+	 */
+	if (ioread32(map + 0x2240c) & 0x2) {
+		pci_info(pdev,
+			 FW_BUG "GPU left initialized by EFI, resetting\n");
+		ret = pci_reset_function(pdev);
+		if (ret < 0)
+			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
+	}
+
+	iounmap(map);
+out_disable:
+	pci_disable_device(pdev);
+}
+
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
+			      PCI_CLASS_DISPLAY_VGA, 8,
+			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot);

Comments

Hi Lyude,

On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> On a very specific subset of ThinkPad P50 SKUs, particularly ones that
> come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
> seems to have a very nasty habit of not always resetting the secondary
> Nvidia GPU between full reboots if the laptop is configured in Hybrid
> Graphics mode. The reason for this happening is unknown, but the
> following steps and possibly a good bit of patience will reproduce the
> issue:
> 
> 1. Boot up the laptop normally in Hybrid graphics mode
> 2. Make sure nouveau is loaded and that the GPU is awake
> 2. Allow the nvidia GPU to runtime suspend itself after being idle
> 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> 4. If nouveau loads up properly, reboot the machine again and go back to
> step 2 until you reproduce the issue
> 
> This results in some very strange behavior: the GPU will
> quite literally be left in exactly the same state it was in when the
> previously booted kernel started the reboot. This has all sorts of bad
> sideaffects: for starters, this completely breaks nouveau starting with a
> mysterious EVO channel failure that happens well before we've actually
> used the EVO channel for anything:

There are a lot of moving parts here that are probably obvious to you
but not to me.  I need help untangling this a bit so I'm comfortable
that we got to the root cause and that we're doing something logical
as opposed to something that just happens to make things work.  I
really don't know enough to even ask the right questions...

Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
including "lspci -vvxxx" and dmidecode for the system.

Is this running a current BIOS?  The date in your log below looks
pretty recent, so I assume it is current.

I assume "hybrid graphics" means you have two GPUs.  Do you select
hybrid graphics mode in the BIOS?

I assume when you say the Nvidia GPU doesn't get reset on a full
reboot, you're talking about a "warm reboot", and that if you actually
remove the power and do a cold reboot, there's no problem?

I assume Nvidia GPU being active means you are using the performance
GPU.  Does that mean the integrated GPU is completely unused and Linux
does nothing at all with it?  Is Linux doing any switching between
them?  If so, how?  I am not 100% confident in the code I've seen that
does the switching.

> nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
> 00000002
> 
> Later on, this causes us to timeout trying to bring up the GR ctx:
> 
> ------------[ cut here ]------------
> nouveau 0000:01:00.0: timeout
> WARNING: CPU: 0 PID: 12 at
> drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> gf100_grctx_generate+0x7b2/0x850 [nouveau]
> Modules linked in: nouveau mxm_wmi i915 crc32c_intel ttm i2c_algo_bit
> serio_raw drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
> xhci_pci drm xhci_hcd i2c_core wmi video
> CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.0.0-rc5Lyude-Test+ #29
> Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET82W (1.55 )
> 12/18/2018
> Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
> RIP: 0010:gf100_grctx_generate+0x7b2/0x850 [nouveau]
> Code: 85 d2 75 04 48 8b 57 10 48 89 95 28 ff ff ff e8 b4 37 0e e1 48 8b
> 95 28 ff ff ff 48 c7 c7 b1 97 57 a0 48 89 c6 e8 5a 38 c0 e0 <0f> 0b e9
> b9 fd ff ff 48 8b 85 60 ff ff ff 48 8b 40 10 48 8b 78 10
> RSP: 0018:ffffc900000b77f0 EFLAGS: 00010286
> RAX: 0000000000000000 RBX: ffff888871af8000 RCX: 0000000000000000
> RDX: ffff88887f41dfe0 RSI: ffff88887f415698 RDI: ffff88887f415698
> RBP: ffffc900000b78c8 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: ffff888872118000
> R13: 0000000000000000 R14: ffffffffa0551420 R15: ffffc900000b7818
> FS:  0000000000000000(0000) GS:ffff88887f400000(0000)
> knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005644d0556ca8 CR3: 0000000002214006 CR4: 00000000003606f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  gf100_gr_init_ctxctl+0x27b/0x2d0 [nouveau]
>  gf100_gr_init+0x5bd/0x5e0 [nouveau]
>  gf100_gr_init_+0x61/0x70 [nouveau]
>  nvkm_gr_init+0x1d/0x20 [nouveau]
>  nvkm_engine_init+0xcb/0x210 [nouveau]
>  nvkm_subdev_init+0xd6/0x230 [nouveau]
>  nvkm_engine_ref.part.0+0x52/0x70 [nouveau]
>  nvkm_engine_ref+0x13/0x20 [nouveau]
>  nvkm_ioctl_new+0x12c/0x260 [nouveau]
>  ? nvkm_fifo_chan_child_del+0xa0/0xa0 [nouveau]
>  ? gf100_gr_dtor+0xe0/0xe0 [nouveau]
>  nvkm_ioctl+0xe2/0x180 [nouveau]
>  nvkm_client_ioctl+0x12/0x20 [nouveau]
>  nvif_object_ioctl+0x47/0x50 [nouveau]
>  nvif_object_init+0xc8/0x120 [nouveau]
>  nvc0_fbcon_accel_init+0x5c/0x960 [nouveau]
>  nouveau_fbcon_create+0x5a5/0x5d0 [nouveau]
>  ? drm_setup_crtcs+0x27b/0xcb0 [drm_kms_helper]
>  ? __lock_is_held+0x5e/0xa0
>  __drm_fb_helper_initial_config_and_unlock+0x27c/0x520 [drm_kms_helper]
>  drm_fb_helper_hotplug_event.part.29+0xae/0xc0 [drm_kms_helper]
>  drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper]
>  nouveau_fbcon_output_poll_changed+0xb8/0x110 [nouveau]
>  drm_kms_helper_hotplug_event+0x2a/0x40 [drm_kms_helper]
>  drm_dp_send_link_address+0x176/0x1c0 [drm_kms_helper]
>  drm_dp_check_and_send_link_address+0xa0/0xb0 [drm_kms_helper]
>  drm_dp_mst_link_probe_work+0xa4/0xc0 [drm_kms_helper]
>  process_one_work+0x22f/0x5c0
>  worker_thread+0x44/0x3a0
>  kthread+0x12b/0x150
>  ? wq_pool_ids_show+0x140/0x140
>  ? kthread_create_on_node+0x60/0x60
>  ret_from_fork+0x3a/0x50
> irq event stamp: 22490
> hardirqs last  enabled at (22489): [<ffffffff8113281d>]
> console_unlock+0x44d/0x5f0
> hardirqs last disabled at (22490): [<ffffffff81001c03>]
> trace_hardirqs_off_thunk+0x1a/0x1c
> softirqs last  enabled at (22486): [<ffffffff81c00330>]
> __do_softirq+0x330/0x44d
> softirqs last disabled at (22479): [<ffffffff810c3105>]
> irq_exit+0xe5/0xf0
> WARNING: CPU: 0 PID: 12 at
> drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> gf100_grctx_generate+0x7b2/0x850 [nouveau]
> ---[ end trace bf0976ed88b122a8 ]---
> nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
> nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
> nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 0000000000008000 engine
> 00 [GR] client 15 [HUB/SCC_NB] reason c4 [] on channel -1 [0000000000
> unknown]
> 
> From which the GPU never manages to recover. Booting without nouveau
> loading causes issues as well, since the GPU starts sending spurious
> interrupts that cause other device's IRQs to get disabled by the kernel:
> 
> irq 16: nobody cared (try booting with the "irqpoll" option)
> …
> handlers:
> [<000000007faa9e99>] i801_isr [i2c_i801]
> Disabling IRQ #16
> …
> serio: RMI4 PS/2 pass-through port at rmi4-00.fn03
> i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> i801_smbus 0000:00:1f.4: Transaction timeout
> rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX
> register (-110).
> i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> i801_smbus 0000:00:1f.4: Transaction timeout
> rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change enabled
> interrupts!
> 
> Which in turn causes the touchpad and sometimes even other things to get
> disabled.
> 
> Since the GPU staying on causes problems even without nouveau's
> intervention, we can't fix this problem from nouveau itself. We have to
> fix it as early as possible in the boot sequence in order to make sure
> that the GPU is in a clean state before it has a chance to spam us with
> interrupts and break things.

Was nouveau loaded *before* the reboot?  Or can you reproduce the
spurious interrupts even if you do a cold reboot without nouveau, then
a warm reboot again without nouveau?

> So to do this, we add a new pci quirk using
> DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
> at boot finishes. From there, we check to make sure that this is indeed
> the specific P50 variant of this GPU. We also make sure that the GPU PCI
> device is advertising NoReset- in order to prevent us from trying to
> reset the GPU when the machine is in Dedicated graphics mode (where the
> GPU being initialized by the BIOS is normal and expected). Finally, we
> try mapping the MMIO space for the GPU which should only work if the GPU
> is actually active in D0 mode. We can then read the magic 0x2240c
> register on the GPU, which will have bit 1 set if the GPU's firmware has
> already been posted during a previous boot. Once we've confirmed all of
> this, we reset the PCI device and re-disable it - bringing the GPU back
> into a healthy state.
> 
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: nouveau@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: Karol Herbst <kherbst@redhat.com>
> Cc: Ben Skeggs <skeggsb@gmail.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b0a413f3f7ca..948492fda8bf 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
>  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
>  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
>  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> +
> +/*
> + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a Nvidia
> + * Quadro M1000M, the BIOS will occasionally make the mistake of not resetting
> + * the nvidia GPU between reboots if the system is configured to use hybrid
> + * graphics mode. This results in the GPU being left in whatever state it was
> + * in during the previous boot which causes spurious interrupts from the GPU,
> + * which in turn cause us to disable the wrong IRQs and end up breaking the
> + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> + *
> + * Luckily, it seems a simple reset of the PCI device for the nvidia GPU
> + * manages to bring the GPU back into a clean state and fix all of these
> + * issues. Additionally since the GPU will report NoReset+ when the machine is
> + * configured in Dedicated display mode, we don't need to worry about
> + * accidentally resetting the GPU when it's supposed to already be
> + * initialized.
> + */
> +static void
> +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> +{
> +	void __iomem *map;
> +	int ret;
> +
> +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> +	    pdev->subsystem_device != 0x222e ||
> +	    !pdev->reset_fn)
> +		return;
> +
> +	/*
> +	 * If we can't enable the device's mmio space, it's probably not even
> +	 * initialized. This is fine, and means we can just skip the quirk
> +	 * entirely.
> +	 */
> +	if (pci_enable_device_mem(pdev)) {
> +		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
> +		return;
> +	}
> +
> +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> +	if (!map) {
> +		pci_err(pdev, "Can't map MMIO space, this is probably very bad\n");
> +		goto out_disable;
> +	}
> +
> +	/*
> +	 * Be extra careful, and make sure that the GPU firmware is posted
> +	 * before trying a reset
> +	 */
> +	if (ioread32(map + 0x2240c) & 0x2) {
> +		pci_info(pdev,
> +			 FW_BUG "GPU left initialized by EFI, resetting\n");
> +		ret = pci_reset_function(pdev);
> +		if (ret < 0)
> +			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
> +	}
> +
> +	iounmap(map);
> +out_disable:
> +	pci_disable_device(pdev);
> +}
> +
> +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> +			      PCI_CLASS_DISPLAY_VGA, 8,
> +			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot);
> -- 
> 2.20.1
>
Hi,

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v4.20.8, v4.19.21, v4.14.99, v4.9.156, v4.4.174, v3.18.134.

v4.20.8: Build OK!
v4.19.21: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")

v4.14.99: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    06dc4ee54e30 ("PCI: Disable MSI for Freescale Layerscape PCIe RC mode")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")

v4.9.156: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    3e13676862f9 ("thunderbolt: Add support for DMA configuration based mailbox")
    46cd4b75cd0e ("efi: Add device path parser")
    58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
    630b3aff8a51 ("treewide: Consolidate Apple DMI checks")
    81a54b5e1986 ("thunderbolt: Let the connection manager handle all notifications")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    9d3cce0b6136 ("thunderbolt: Introduce thunderbolt bus and connection manager")
    ac6c44de503e ("thunderbolt: Expose get_route() to other files")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    bfe778ac4982 ("thunderbolt: Convert switch to a device")
    c9cc3aaa0281 ("thunderbolt: Use Device ROM retrieved from EFI")
    da2da04b8d44 ("thunderbolt: Rework capability handling")
    f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v4.4.174: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    14d2000182ed ("drm/radeon: Defer probe if gmux is present but its driver isn't")
    156d7d4120e1 ("vga_switcheroo: Add handler flags infrastructure")
    3a848662c751 ("vga_switcheroo: Prettify documentation")
    412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when amdkfd not loaded")
    704ab614ec12 ("drm/i915: Defer probe if gmux is present but its driver isn't")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    989561de9b51 ("PM / Domains: add setter for dev.pm_domain")
    98b3a3402eb6 ("drm/nouveau: Defer probe if gmux is present but its driver isn't")
    a345918d6ee6 ("vga_switcheroo: Support deferred probing of audio clients")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    b00e5334ab1b ("vga_switcheroo: Add helper for deferred probing")
    b5f88dd1d6ef ("Revert "ACPI / LPSS: allow to use specific PM domain during ->probe()"")
    c1e1655bb892 ("apple-gmux: Assign apple_gmux_data before registering")
    c68f4528a2e9 ("drm/amdkfd: Track when module's init is complete")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v3.18.134: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    083dba02947d ("drm/nouveau/device: recognise GM204")
    2f4a58e852d1 ("drm/nouveau/subdev: always upcast through nouveau_subdev()/nouveau_engine()")
    4766ec53945f ("drm/nouveau/bios: add parsing of BIT M(v2) +0x03 table")
    50e216d6e7c3 ("drm/nouveau/bios: add parsing of pmu image tables")
    5444204036b2 ("drm/nouveau: switch to new-style timer macros")
    7bb6d4428d3d ("drm/nouveau: move the (far too many...) different s/r paths to the same place")
    8d5e3af15c79 ("drm/nouveau/device: Add support for GK208B, resolves bug 86935")
    8d85e06b5e04 ("drm/nouveau/bios: add pci data structure parsing")
    989aa5b76ad2 ("drm/nouveau/nvif: namespace of nvkm accessors (no binary change)")
    a01ca78c8f11 ("drm/nouveau/nvif: simplify and tidy library interfaces")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    ad4a36263535 ("drm/nouveau/bios: split out shadow methods")
    b71a1344ec20 ("drm/nouveau/bios: add NPDE parsing")
    ba6e34e61271 ("drm/gm204/devinit: initial implementation")
    be83cd4ef9a2 ("drm/nouveau: finalise nvkm namespace switch (no binary change)")
    c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
    cb8bb9cedb60 ("drm/nouveau/tmr: cosmetic changes")
    d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
    f3867f439fd6 ("drm/nouveau/clk: rename from clock (no binary change)")
    f8a8546194d7 ("drm/nouveau/clk: allow non-blocking for nouveau_clock_astate()")


How should we proceed with this patch?

--
Thanks,
Sasha
On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> Hi Lyude,
> 
> On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > On a very specific subset of ThinkPad P50 SKUs, particularly ones that
> > come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
> > seems to have a very nasty habit of not always resetting the secondary
> > Nvidia GPU between full reboots if the laptop is configured in Hybrid
> > Graphics mode. The reason for this happening is unknown, but the
> > following steps and possibly a good bit of patience will reproduce the
> > issue:
> > 
> > 1. Boot up the laptop normally in Hybrid graphics mode
> > 2. Make sure nouveau is loaded and that the GPU is awake
> > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> > 4. If nouveau loads up properly, reboot the machine again and go back to
> > step 2 until you reproduce the issue
> > 
> > This results in some very strange behavior: the GPU will
> > quite literally be left in exactly the same state it was in when the
> > previously booted kernel started the reboot. This has all sorts of bad
> > sideaffects: for starters, this completely breaks nouveau starting with a
> > mysterious EVO channel failure that happens well before we've actually
> > used the EVO channel for anything:
> 
> There are a lot of moving parts here that are probably obvious to you
> but not to me.  I need help untangling this a bit so I'm comfortable
> that we got to the root cause and that we're doing something logical
> as opposed to something that just happens to make things work.  I
> really don't know enough to even ask the right questions...

I completely understand! I'm pretty sure I'd be just as skeptical if I was in
your position reviewing a patch like this :P

> 
> Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
> including "lspci -vvxxx" and dmidecode for the system.
> 
Not yet, but there has been discussion about this between nouveau developers
on our IRC channel.

> Is this running a current BIOS?  The date in your log below looks
> pretty recent, so I assume it is current.

Yes, this is the most up to date BIOS available for this system.

> 
> I assume "hybrid graphics" means you have two GPUs.  Do you select
> hybrid graphics mode in the BIOS?

Yes, the P50 has two available modes in the BIOS: Dedicated (e.g. only
the nvidia GPU is used for everything), and Hybrid (i915 drives the
built-in display panel, nouveau drives everything else). This bug only
seems to occur in Hybrid mode.

> 
> I assume when you say the Nvidia GPU doesn't get reset on a full
> reboot, you're talking about a "warm reboot", and that if you actually
> remove the power and do a cold reboot, there's no problem?

If you meant "unplugging the power adapter" when you said cutting the
power we don't need to go that far, but shutting down the machine and
restarting it by hand does avoid the problem yes.

> 
> I assume Nvidia GPU being active means you are using the performance
> GPU.  Does that mean the integrated GPU is completely unused and Linux
> does nothing at all with it?  Is Linux doing any switching between
> them?  If so, how?  I am not 100% confident in the code I've seen that
> does the switching.

"Switching" isn't really the right word to describe it these days as the
process for how this is handled has changed quite a bit in the last few
years. As I mentioned above, the main intel GPU is used for driving the
built-in display. As for the nvidia GPU, it's used to drive any kind of
external displays connected to the P50 and can also be used to do
rendering through DRI PRIME. The connector hookups are mostly hardcoded
as there isn't really much of a mux, unlike the old days where we could
actually do things like switch which GPU was driving the internal
display on the fly with  vga-switcheroo using the _DSM methods provided
by ACPI.

Nowadays muxless laptops like the ThinkPad P50 don't make much use of
_DSM for power management and instead just runtime suspend the dedicated
nvidia GPU when it's not in use. We rely on the PCI subsystem to invoke
the _PR3 ACPI methods for suspending and resuming the GPU and don't
handle much of it ourselves anymore:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/nouveau/nouveau_drm.c?h=v5.0-rc6#n860

(You can ignore the call to nouveau_switcheroo_optimus_dsm() there; it
 doesn't do anything on systems like the P50 where we detect _PR3)

Additionally-if you see any problems with how we're handling things
there we're all ears! We've been trying to fix as many issues with
runtime PM as we can find.

Something else to consider here too: I've only ever managed to reproduce
this issue on this specific P50 SKU. Since I work on Desktop engineering
at Red Hat we have access to a very large number of laptops with hybrid
GPU setups. Interestingly I haven't ever reproduced anything like this
on any of them, even P50 SKUs with the M2000M GPU instead of the M1000M
(which are almost identical, they're both GM107 chips) I can follow the
same steps that I followed to reproduce this bug and it never appears.

Another thing to note: this bug also doesn't appear to happen 100% of
the time. Some warm reboots the GPU will be reset by the BIOS perfectly
fine.

> 
> > nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
> > 00000002
> > 
> > Later on, this causes us to timeout trying to bring up the GR ctx:
> > 
> > ------------[ cut here ]------------
> > nouveau 0000:01:00.0: timeout
> > WARNING: CPU: 0 PID: 12 at
> > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > Modules linked in: nouveau mxm_wmi i915 crc32c_intel ttm i2c_algo_bit
> > serio_raw drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
> > xhci_pci drm xhci_hcd i2c_core wmi video
> > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.0.0-rc5Lyude-Test+ #29
> > Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET82W (1.55 )
> > 12/18/2018
> > Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
> > RIP: 0010:gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > Code: 85 d2 75 04 48 8b 57 10 48 89 95 28 ff ff ff e8 b4 37 0e e1 48 8b
> > 95 28 ff ff ff 48 c7 c7 b1 97 57 a0 48 89 c6 e8 5a 38 c0 e0 <0f> 0b e9
> > b9 fd ff ff 48 8b 85 60 ff ff ff 48 8b 40 10 48 8b 78 10
> > RSP: 0018:ffffc900000b77f0 EFLAGS: 00010286
> > RAX: 0000000000000000 RBX: ffff888871af8000 RCX: 0000000000000000
> > RDX: ffff88887f41dfe0 RSI: ffff88887f415698 RDI: ffff88887f415698
> > RBP: ffffc900000b78c8 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: ffff888872118000
> > R13: 0000000000000000 R14: ffffffffa0551420 R15: ffffc900000b7818
> > FS:  0000000000000000(0000) GS:ffff88887f400000(0000)
> > knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00005644d0556ca8 CR3: 0000000002214006 CR4: 00000000003606f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  gf100_gr_init_ctxctl+0x27b/0x2d0 [nouveau]
> >  gf100_gr_init+0x5bd/0x5e0 [nouveau]
> >  gf100_gr_init_+0x61/0x70 [nouveau]
> >  nvkm_gr_init+0x1d/0x20 [nouveau]
> >  nvkm_engine_init+0xcb/0x210 [nouveau]
> >  nvkm_subdev_init+0xd6/0x230 [nouveau]
> >  nvkm_engine_ref.part.0+0x52/0x70 [nouveau]
> >  nvkm_engine_ref+0x13/0x20 [nouveau]
> >  nvkm_ioctl_new+0x12c/0x260 [nouveau]
> >  ? nvkm_fifo_chan_child_del+0xa0/0xa0 [nouveau]
> >  ? gf100_gr_dtor+0xe0/0xe0 [nouveau]
> >  nvkm_ioctl+0xe2/0x180 [nouveau]
> >  nvkm_client_ioctl+0x12/0x20 [nouveau]
> >  nvif_object_ioctl+0x47/0x50 [nouveau]
> >  nvif_object_init+0xc8/0x120 [nouveau]
> >  nvc0_fbcon_accel_init+0x5c/0x960 [nouveau]
> >  nouveau_fbcon_create+0x5a5/0x5d0 [nouveau]
> >  ? drm_setup_crtcs+0x27b/0xcb0 [drm_kms_helper]
> >  ? __lock_is_held+0x5e/0xa0
> >  __drm_fb_helper_initial_config_and_unlock+0x27c/0x520 [drm_kms_helper]
> >  drm_fb_helper_hotplug_event.part.29+0xae/0xc0 [drm_kms_helper]
> >  drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper]
> >  nouveau_fbcon_output_poll_changed+0xb8/0x110 [nouveau]
> >  drm_kms_helper_hotplug_event+0x2a/0x40 [drm_kms_helper]
> >  drm_dp_send_link_address+0x176/0x1c0 [drm_kms_helper]
> >  drm_dp_check_and_send_link_address+0xa0/0xb0 [drm_kms_helper]
> >  drm_dp_mst_link_probe_work+0xa4/0xc0 [drm_kms_helper]
> >  process_one_work+0x22f/0x5c0
> >  worker_thread+0x44/0x3a0
> >  kthread+0x12b/0x150
> >  ? wq_pool_ids_show+0x140/0x140
> >  ? kthread_create_on_node+0x60/0x60
> >  ret_from_fork+0x3a/0x50
> > irq event stamp: 22490
> > hardirqs last  enabled at (22489): [<ffffffff8113281d>]
> > console_unlock+0x44d/0x5f0
> > hardirqs last disabled at (22490): [<ffffffff81001c03>]
> > trace_hardirqs_off_thunk+0x1a/0x1c
> > softirqs last  enabled at (22486): [<ffffffff81c00330>]
> > __do_softirq+0x330/0x44d
> > softirqs last disabled at (22479): [<ffffffff810c3105>]
> > irq_exit+0xe5/0xf0
> > WARNING: CPU: 0 PID: 12 at
> > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > ---[ end trace bf0976ed88b122a8 ]---
> > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
> > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy: 1)
> > nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 0000000000008000 engine
> > 00 [GR] client 15 [HUB/SCC_NB] reason c4 [] on channel -1 [0000000000
> > unknown]
> > 
> > From which the GPU never manages to recover. Booting without nouveau
> > loading causes issues as well, since the GPU starts sending spurious
> > interrupts that cause other device's IRQs to get disabled by the kernel:
> > 
> > irq 16: nobody cared (try booting with the "irqpoll" option)
> > …
> > handlers:
> > [<000000007faa9e99>] i801_isr [i2c_i801]
> > Disabling IRQ #16
> > …
> > serio: RMI4 PS/2 pass-through port at rmi4-00.fn03
> > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > i801_smbus 0000:00:1f.4: Transaction timeout
> > rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX
> > register (-110).
> > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > i801_smbus 0000:00:1f.4: Transaction timeout
> > rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change enabled
> > interrupts!
> > 
> > Which in turn causes the touchpad and sometimes even other things to get
> > disabled.
> > 
> > Since the GPU staying on causes problems even without nouveau's
> > intervention, we can't fix this problem from nouveau itself. We have to
> > fix it as early as possible in the boot sequence in order to make sure
> > that the GPU is in a clean state before it has a chance to spam us with
> > interrupts and break things.
> 
> Was nouveau loaded *before* the reboot?  Or can you reproduce the
> spurious interrupts even if you do a cold reboot without nouveau, then
> a warm reboot again without nouveau?

Nouveau was loaded before the reboot, yes, and as far as I'm aware this
bug won't show up following the steps you described here. We wouldn't
really notice the interrupts if this bug happened without nouveau loaded
(since the BIOS doesn't arm them). However, I can confirm it's being
reset each on each warm reboot when nouveau's completely disabled by
sticking values into some MMIO registers we know the VBIOS doesn't touch
followed by rebooting in order to see if they retain their value (this
is how I discovered that the GPU wasn't being power cycled in the first
place, if the values I stick into said registers gets cleared after
reboot then the GPU was reset, otherwise it wasn't).


> 
> > So to do this, we add a new pci quirk using
> > DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
> > at boot finishes. From there, we check to make sure that this is indeed
> > the specific P50 variant of this GPU. We also make sure that the GPU PCI
> > device is advertising NoReset- in order to prevent us from trying to
> > reset the GPU when the machine is in Dedicated graphics mode (where the
> > GPU being initialized by the BIOS is normal and expected). Finally, we
> > try mapping the MMIO space for the GPU which should only work if the GPU
> > is actually active in D0 mode. We can then read the magic 0x2240c
> > register on the GPU, which will have bit 1 set if the GPU's firmware has
> > already been posted during a previous boot. Once we've confirmed all of
> > this, we reset the PCI device and re-disable it - bringing the GPU back
> > into a healthy state.
> > 
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > Cc: nouveau@lists.freedesktop.org
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: Karol Herbst <kherbst@redhat.com>
> > Cc: Ben Skeggs <skeggsb@gmail.com>
> > Cc: stable@vger.kernel.org
> > ---
> >  drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 65 insertions(+)
> > 
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index b0a413f3f7ca..948492fda8bf 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
> >  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
> >  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
> >  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> > +
> > +/*
> > + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a Nvidia
> > + * Quadro M1000M, the BIOS will occasionally make the mistake of not
> > resetting
> > + * the nvidia GPU between reboots if the system is configured to use
> > hybrid
> > + * graphics mode. This results in the GPU being left in whatever state it
> > was
> > + * in during the previous boot which causes spurious interrupts from the
> > GPU,
> > + * which in turn cause us to disable the wrong IRQs and end up breaking
> > the
> > + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> > + *
> > + * Luckily, it seems a simple reset of the PCI device for the nvidia GPU
> > + * manages to bring the GPU back into a clean state and fix all of these
> > + * issues. Additionally since the GPU will report NoReset+ when the
> > machine is
> > + * configured in Dedicated display mode, we don't need to worry about
> > + * accidentally resetting the GPU when it's supposed to already be
> > + * initialized.
> > + */
> > +static void
> > +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> > +{
> > +	void __iomem *map;
> > +	int ret;
> > +
> > +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> > +	    pdev->subsystem_device != 0x222e ||
> > +	    !pdev->reset_fn)
> > +		return;
> > +
> > +	/*
> > +	 * If we can't enable the device's mmio space, it's probably not even
> > +	 * initialized. This is fine, and means we can just skip the quirk
> > +	 * entirely.
> > +	 */
> > +	if (pci_enable_device_mem(pdev)) {
> > +		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
> > +		return;
> > +	}
> > +
> > +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> > +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> > +	if (!map) {
> > +		pci_err(pdev, "Can't map MMIO space, this is probably very
> > bad\n");
> > +		goto out_disable;
> > +	}
> > +
> > +	/*
> > +	 * Be extra careful, and make sure that the GPU firmware is posted
> > +	 * before trying a reset
> > +	 */
> > +	if (ioread32(map + 0x2240c) & 0x2) {
> > +		pci_info(pdev,
> > +			 FW_BUG "GPU left initialized by EFI, resetting\n");
> > +		ret = pci_reset_function(pdev);
> > +		if (ret < 0)
> > +			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
> > +	}
> > +
> > +	iounmap(map);
> > +out_disable:
> > +	pci_disable_device(pdev);
> > +}
> > +
> > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> > +			      PCI_CLASS_DISPLAY_VGA, 8,
> > +			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot)
> > ;
> > -- 
> > 2.20.1
> >
Hi,

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v4.20.8, v4.19.21, v4.14.99, v4.9.156, v4.4.174, v3.18.134.

v4.20.8: Build OK!
v4.19.21: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")

v4.14.99: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    06dc4ee54e30 ("PCI: Disable MSI for Freescale Layerscape PCIe RC mode")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")

v4.9.156: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    3e13676862f9 ("thunderbolt: Add support for DMA configuration based mailbox")
    46cd4b75cd0e ("efi: Add device path parser")
    58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
    630b3aff8a51 ("treewide: Consolidate Apple DMI checks")
    81a54b5e1986 ("thunderbolt: Let the connection manager handle all notifications")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    9d3cce0b6136 ("thunderbolt: Introduce thunderbolt bus and connection manager")
    ac6c44de503e ("thunderbolt: Expose get_route() to other files")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    bfe778ac4982 ("thunderbolt: Convert switch to a device")
    c9cc3aaa0281 ("thunderbolt: Use Device ROM retrieved from EFI")
    da2da04b8d44 ("thunderbolt: Rework capability handling")
    f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v4.4.174: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    14d2000182ed ("drm/radeon: Defer probe if gmux is present but its driver isn't")
    156d7d4120e1 ("vga_switcheroo: Add handler flags infrastructure")
    3a848662c751 ("vga_switcheroo: Prettify documentation")
    412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when amdkfd not loaded")
    704ab614ec12 ("drm/i915: Defer probe if gmux is present but its driver isn't")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    989561de9b51 ("PM / Domains: add setter for dev.pm_domain")
    98b3a3402eb6 ("drm/nouveau: Defer probe if gmux is present but its driver isn't")
    a345918d6ee6 ("vga_switcheroo: Support deferred probing of audio clients")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    b00e5334ab1b ("vga_switcheroo: Add helper for deferred probing")
    b5f88dd1d6ef ("Revert "ACPI / LPSS: allow to use specific PM domain during ->probe()"")
    c1e1655bb892 ("apple-gmux: Assign apple_gmux_data before registering")
    c68f4528a2e9 ("drm/amdkfd: Track when module's init is complete")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v3.18.134: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    083dba02947d ("drm/nouveau/device: recognise GM204")
    2f4a58e852d1 ("drm/nouveau/subdev: always upcast through nouveau_subdev()/nouveau_engine()")
    4766ec53945f ("drm/nouveau/bios: add parsing of BIT M(v2) +0x03 table")
    50e216d6e7c3 ("drm/nouveau/bios: add parsing of pmu image tables")
    5444204036b2 ("drm/nouveau: switch to new-style timer macros")
    7bb6d4428d3d ("drm/nouveau: move the (far too many...) different s/r paths to the same place")
    8d5e3af15c79 ("drm/nouveau/device: Add support for GK208B, resolves bug 86935")
    8d85e06b5e04 ("drm/nouveau/bios: add pci data structure parsing")
    989aa5b76ad2 ("drm/nouveau/nvif: namespace of nvkm accessors (no binary change)")
    a01ca78c8f11 ("drm/nouveau/nvif: simplify and tidy library interfaces")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    ad4a36263535 ("drm/nouveau/bios: split out shadow methods")
    b71a1344ec20 ("drm/nouveau/bios: add NPDE parsing")
    ba6e34e61271 ("drm/gm204/devinit: initial implementation")
    be83cd4ef9a2 ("drm/nouveau: finalise nvkm namespace switch (no binary change)")
    c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
    cb8bb9cedb60 ("drm/nouveau/tmr: cosmetic changes")
    d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
    f3867f439fd6 ("drm/nouveau/clk: rename from clock (no binary change)")
    f8a8546194d7 ("drm/nouveau/clk: allow non-blocking for nouveau_clock_astate()")


How should we proceed with this patch?

--
Thanks,
Sasha
Hi,

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v4.20.8, v4.19.21, v4.14.99, v4.9.156, v4.4.174, v3.18.134.

v4.20.8: Build OK!
v4.19.21: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")

v4.14.99: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    06dc4ee54e30 ("PCI: Disable MSI for Freescale Layerscape PCIe RC mode")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")

v4.9.156: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    3e13676862f9 ("thunderbolt: Add support for DMA configuration based mailbox")
    46cd4b75cd0e ("efi: Add device path parser")
    58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
    630b3aff8a51 ("treewide: Consolidate Apple DMI checks")
    81a54b5e1986 ("thunderbolt: Let the connection manager handle all notifications")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    9d3cce0b6136 ("thunderbolt: Introduce thunderbolt bus and connection manager")
    ac6c44de503e ("thunderbolt: Expose get_route() to other files")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    bfe778ac4982 ("thunderbolt: Convert switch to a device")
    c9cc3aaa0281 ("thunderbolt: Use Device ROM retrieved from EFI")
    da2da04b8d44 ("thunderbolt: Rework capability handling")
    f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v4.4.174: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    14d2000182ed ("drm/radeon: Defer probe if gmux is present but its driver isn't")
    156d7d4120e1 ("vga_switcheroo: Add handler flags infrastructure")
    3a848662c751 ("vga_switcheroo: Prettify documentation")
    412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when amdkfd not loaded")
    704ab614ec12 ("drm/i915: Defer probe if gmux is present but its driver isn't")
    8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
    989561de9b51 ("PM / Domains: add setter for dev.pm_domain")
    98b3a3402eb6 ("drm/nouveau: Defer probe if gmux is present but its driver isn't")
    a345918d6ee6 ("vga_switcheroo: Support deferred probing of audio clients")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    b00e5334ab1b ("vga_switcheroo: Add helper for deferred probing")
    b5f88dd1d6ef ("Revert "ACPI / LPSS: allow to use specific PM domain during ->probe()"")
    c1e1655bb892 ("apple-gmux: Assign apple_gmux_data before registering")
    c68f4528a2e9 ("drm/amdkfd: Track when module's init is complete")
    fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")

v3.18.134: Failed to apply! Possible dependencies:
    01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
    07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
    083dba02947d ("drm/nouveau/device: recognise GM204")
    2f4a58e852d1 ("drm/nouveau/subdev: always upcast through nouveau_subdev()/nouveau_engine()")
    4766ec53945f ("drm/nouveau/bios: add parsing of BIT M(v2) +0x03 table")
    50e216d6e7c3 ("drm/nouveau/bios: add parsing of pmu image tables")
    5444204036b2 ("drm/nouveau: switch to new-style timer macros")
    7bb6d4428d3d ("drm/nouveau: move the (far too many...) different s/r paths to the same place")
    8d5e3af15c79 ("drm/nouveau/device: Add support for GK208B, resolves bug 86935")
    8d85e06b5e04 ("drm/nouveau/bios: add pci data structure parsing")
    989aa5b76ad2 ("drm/nouveau/nvif: namespace of nvkm accessors (no binary change)")
    a01ca78c8f11 ("drm/nouveau/nvif: simplify and tidy library interfaces")
    ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
    ad4a36263535 ("drm/nouveau/bios: split out shadow methods")
    b71a1344ec20 ("drm/nouveau/bios: add NPDE parsing")
    ba6e34e61271 ("drm/gm204/devinit: initial implementation")
    be83cd4ef9a2 ("drm/nouveau: finalise nvkm namespace switch (no binary change)")
    c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
    cb8bb9cedb60 ("drm/nouveau/tmr: cosmetic changes")
    d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
    f3867f439fd6 ("drm/nouveau/clk: rename from clock (no binary change)")
    f8a8546194d7 ("drm/nouveau/clk: allow non-blocking for nouveau_clock_astate()")


How should we proceed with this patch?

--
Thanks,
Sasha
On Mon, Feb 18, 2019 at 3:14 PM Sasha Levin <sashal@kernel.org> wrote:
>
> Hi,
>
> [This is an automated email]
>
> This commit has been processed because it contains a -stable tag.
> The stable tag indicates that it's relevant for the following trees: all
>
> The bot has tested the following trees: v4.20.8, v4.19.21, v4.14.99, v4.9.156, v4.4.174, v3.18.134.
>
> v4.20.8: Build OK!
> v4.19.21: Failed to apply! Possible dependencies:
>     01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
>
> v4.14.99: Failed to apply! Possible dependencies:
>     01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
>     06dc4ee54e30 ("PCI: Disable MSI for Freescale Layerscape PCIe RC mode")
>     07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
>     8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
>     ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
>
> v4.9.156: Failed to apply! Possible dependencies:
>     01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
>     07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
>     3e13676862f9 ("thunderbolt: Add support for DMA configuration based mailbox")
>     46cd4b75cd0e ("efi: Add device path parser")
>     58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
>     630b3aff8a51 ("treewide: Consolidate Apple DMI checks")
>     81a54b5e1986 ("thunderbolt: Let the connection manager handle all notifications")
>     8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
>     9d3cce0b6136 ("thunderbolt: Introduce thunderbolt bus and connection manager")
>     ac6c44de503e ("thunderbolt: Expose get_route() to other files")
>     ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
>     bfe778ac4982 ("thunderbolt: Convert switch to a device")
>     c9cc3aaa0281 ("thunderbolt: Use Device ROM retrieved from EFI")
>     da2da04b8d44 ("thunderbolt: Rework capability handling")
>     f67cf491175a ("thunderbolt: Add support for Internal Connection Manager (ICM)")
>     fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")
>
> v4.4.174: Failed to apply! Possible dependencies:
>     01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
>     07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
>     14d2000182ed ("drm/radeon: Defer probe if gmux is present but its driver isn't")
>     156d7d4120e1 ("vga_switcheroo: Add handler flags infrastructure")
>     3a848662c751 ("vga_switcheroo: Prettify documentation")
>     412c8f7de011 ("drm/radeon: Return -EPROBE_DEFER when amdkfd not loaded")
>     704ab614ec12 ("drm/i915: Defer probe if gmux is present but its driver isn't")
>     8948ca1a12c9 ("vga_switcheroo: Deduplicate power state tracking")
>     989561de9b51 ("PM / Domains: add setter for dev.pm_domain")
>     98b3a3402eb6 ("drm/nouveau: Defer probe if gmux is present but its driver isn't")
>     a345918d6ee6 ("vga_switcheroo: Support deferred probing of audio clients")
>     ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
>     b00e5334ab1b ("vga_switcheroo: Add helper for deferred probing")
>     b5f88dd1d6ef ("Revert "ACPI / LPSS: allow to use specific PM domain during ->probe()"")
>     c1e1655bb892 ("apple-gmux: Assign apple_gmux_data before registering")
>     c68f4528a2e9 ("drm/amdkfd: Track when module's init is complete")
>     fa6d513aefe4 ("drivers:gpu: vga :vga_switcheroo.c : Fixed some coding style issues")
>
> v3.18.134: Failed to apply! Possible dependencies:
>     01d5d7fa8376 ("PCI: Add macro for Switchtec quirk declarations")
>     07f4f97d7b4b ("vga_switcheroo: Use device link for HDA controller")
>     083dba02947d ("drm/nouveau/device: recognise GM204")
>     2f4a58e852d1 ("drm/nouveau/subdev: always upcast through nouveau_subdev()/nouveau_engine()")
>     4766ec53945f ("drm/nouveau/bios: add parsing of BIT M(v2) +0x03 table")
>     50e216d6e7c3 ("drm/nouveau/bios: add parsing of pmu image tables")
>     5444204036b2 ("drm/nouveau: switch to new-style timer macros")
>     7bb6d4428d3d ("drm/nouveau: move the (far too many...) different s/r paths to the same place")
>     8d5e3af15c79 ("drm/nouveau/device: Add support for GK208B, resolves bug 86935")
>     8d85e06b5e04 ("drm/nouveau/bios: add pci data structure parsing")
>     989aa5b76ad2 ("drm/nouveau/nvif: namespace of nvkm accessors (no binary change)")
>     a01ca78c8f11 ("drm/nouveau/nvif: simplify and tidy library interfaces")
>     ad281ecf1c7d ("PCI: Add DMA alias quirk for Microsemi Switchtec NTB")
>     ad4a36263535 ("drm/nouveau/bios: split out shadow methods")
>     b71a1344ec20 ("drm/nouveau/bios: add NPDE parsing")
>     ba6e34e61271 ("drm/gm204/devinit: initial implementation")
>     be83cd4ef9a2 ("drm/nouveau: finalise nvkm namespace switch (no binary change)")
>     c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
>     cb8bb9cedb60 ("drm/nouveau/tmr: cosmetic changes")
>     d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
>     f3867f439fd6 ("drm/nouveau/clk: rename from clock (no binary change)")
>     f8a8546194d7 ("drm/nouveau/clk: allow non-blocking for nouveau_clock_astate()")
>
>
> How should we proceed with this patch?

Is there any way we can turn off this automated checking for a while?
At this stage, where we're just trying to discuss the issue, these
emails just clutter things up.
[note to David Ober: you -should- be able to reply to this, hopefully, but I
haven't actually tested that so results may vary]

Hi again! Sorry I didn't fully answer all of the questions you originally
asked in this email, I had to get in contact with Lenovo to make sure that it
was OK for me to disclose more details on this bug (and I had PTO scheduled
immediately after I asked). I've added David Ober from Lenovo to this thread
as well. So now that I've got Lenovo's approval I can answer those questions,
and give some better answers for the others! (see below)


On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > Hi Lyude,
> > 
> > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > On a very specific subset of ThinkPad P50 SKUs, particularly ones that
> > > come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
> > > seems to have a very nasty habit of not always resetting the secondary
> > > Nvidia GPU between full reboots if the laptop is configured in Hybrid
> > > Graphics mode. The reason for this happening is unknown, but the
> > > following steps and possibly a good bit of patience will reproduce the
> > > issue:
> > > 
> > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> > > 4. If nouveau loads up properly, reboot the machine again and go back to
> > > step 2 until you reproduce the issue
> > > 
> > > This results in some very strange behavior: the GPU will
> > > quite literally be left in exactly the same state it was in when the
> > > previously booted kernel started the reboot. This has all sorts of bad
> > > sideaffects: for starters, this completely breaks nouveau starting with
> > > a
> > > mysterious EVO channel failure that happens well before we've actually
> > > used the EVO channel for anything:
> > 
> > There are a lot of moving parts here that are probably obvious to you
> > but not to me.  I need help untangling this a bit so I'm comfortable
> > that we got to the root cause and that we're doing something logical
> > as opposed to something that just happens to make things work.  I
> > really don't know enough to even ask the right questions...
> 
> I completely understand! I'm pretty sure I'd be just as skeptical if I was
> in
> your position reviewing a patch like this :P
> 
> > Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
> > including "lspci -vvxxx" and dmidecode for the system.
> > 
> Not yet, but there has been discussion about this between nouveau developers
> on our IRC channel.
I lied: yes there actually is a bug report for this, but it's currently on the
Red Hat bugzilla. I can get more information from it if you need (with
lenovo's approval of course).

> 
> > Is this running a current BIOS?  The date in your log below looks
> > pretty recent, so I assume it is current.
> 
> Yes, this is the most up to date BIOS available for this system.

And additionally: I've been working with Lenovo on this issue for a couple of
months now, and we've gone through dozens of different trial BIOSes with no
success thus far. However, Lenovo is currently working on trying to add this
workaround into their BIOS but I've been told that this change is going to
take a decent amount of time since they need to test it across multiple
operating systems. I'd be happy to come back and add a conditional later to
turn this workaround off for later BIOS versions once Lenovo has released a
proper fix.

With all of that being said, [how] do you think we should proceed?

> 
> > I assume "hybrid graphics" means you have two GPUs.  Do you select
> > hybrid graphics mode in the BIOS?
> 
> Yes, the P50 has two available modes in the BIOS: Dedicated (e.g. only
> the nvidia GPU is used for everything), and Hybrid (i915 drives the
> built-in display panel, nouveau drives everything else). This bug only
> seems to occur in Hybrid mode.
> 
> > I assume when you say the Nvidia GPU doesn't get reset on a full
> > reboot, you're talking about a "warm reboot", and that if you actually
> > remove the power and do a cold reboot, there's no problem?
> 
> If you meant "unplugging the power adapter" when you said cutting the
> power we don't need to go that far, but shutting down the machine and
> restarting it by hand does avoid the problem yes.
> 
> > I assume Nvidia GPU being active means you are using the performance
> > GPU.  Does that mean the integrated GPU is completely unused and Linux
> > does nothing at all with it?  Is Linux doing any switching between
> > them?  If so, how?  I am not 100% confident in the code I've seen that
> > does the switching.
> 
> "Switching" isn't really the right word to describe it these days as the
> process for how this is handled has changed quite a bit in the last few
> years. As I mentioned above, the main intel GPU is used for driving the
> built-in display. As for the nvidia GPU, it's used to drive any kind of
> external displays connected to the P50 and can also be used to do
> rendering through DRI PRIME. The connector hookups are mostly hardcoded
> as there isn't really much of a mux, unlike the old days where we could
> actually do things like switch which GPU was driving the internal
> display on the fly with  vga-switcheroo using the _DSM methods provided
> by ACPI.
> 
> Nowadays muxless laptops like the ThinkPad P50 don't make much use of
> _DSM for power management and instead just runtime suspend the dedicated
> nvidia GPU when it's not in use. We rely on the PCI subsystem to invoke
> the _PR3 ACPI methods for suspending and resuming the GPU and don't
> handle much of it ourselves anymore:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/nouveau/nouveau_drm.c?h=v5.0-rc6#n860
> 
> (You can ignore the call to nouveau_switcheroo_optimus_dsm() there; it
>  doesn't do anything on systems like the P50 where we detect _PR3)
> 
> Additionally-if you see any problems with how we're handling things
> there we're all ears! We've been trying to fix as many issues with
> runtime PM as we can find.
> 
> Something else to consider here too: I've only ever managed to reproduce
> this issue on this specific P50 SKU. Since I work on Desktop engineering
> at Red Hat we have access to a very large number of laptops with hybrid
> GPU setups. Interestingly I haven't ever reproduced anything like this
> on any of them, even P50 SKUs with the M2000M GPU instead of the M1000M
> (which are almost identical, they're both GM107 chips) I can follow the
> same steps that I followed to reproduce this bug and it never appears.
> 
> Another thing to note: this bug also doesn't appear to happen 100% of
> the time. Some warm reboots the GPU will be reset by the BIOS perfectly
> fine.
> 
> > > nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
> > > 00000002
> > > 
> > > Later on, this causes us to timeout trying to bring up the GR ctx:
> > > 
> > > ------------[ cut here ]------------
> > > nouveau 0000:01:00.0: timeout
> > > WARNING: CPU: 0 PID: 12 at
> > > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > Modules linked in: nouveau mxm_wmi i915 crc32c_intel ttm i2c_algo_bit
> > > serio_raw drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
> > > xhci_pci drm xhci_hcd i2c_core wmi video
> > > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.0.0-rc5Lyude-Test+ #29
> > > Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET82W (1.55 )
> > > 12/18/2018
> > > Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
> > > RIP: 0010:gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > Code: 85 d2 75 04 48 8b 57 10 48 89 95 28 ff ff ff e8 b4 37 0e e1 48 8b
> > > 95 28 ff ff ff 48 c7 c7 b1 97 57 a0 48 89 c6 e8 5a 38 c0 e0 <0f> 0b e9
> > > b9 fd ff ff 48 8b 85 60 ff ff ff 48 8b 40 10 48 8b 78 10
> > > RSP: 0018:ffffc900000b77f0 EFLAGS: 00010286
> > > RAX: 0000000000000000 RBX: ffff888871af8000 RCX: 0000000000000000
> > > RDX: ffff88887f41dfe0 RSI: ffff88887f415698 RDI: ffff88887f415698
> > > RBP: ffffc900000b78c8 R08: 0000000000000000 R09: 0000000000000000
> > > R10: 0000000000000000 R11: 0000000000000000 R12: ffff888872118000
> > > R13: 0000000000000000 R14: ffffffffa0551420 R15: ffffc900000b7818
> > > FS:  0000000000000000(0000) GS:ffff88887f400000(0000)
> > > knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 00005644d0556ca8 CR3: 0000000002214006 CR4: 00000000003606f0
> > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > Call Trace:
> > >  gf100_gr_init_ctxctl+0x27b/0x2d0 [nouveau]
> > >  gf100_gr_init+0x5bd/0x5e0 [nouveau]
> > >  gf100_gr_init_+0x61/0x70 [nouveau]
> > >  nvkm_gr_init+0x1d/0x20 [nouveau]
> > >  nvkm_engine_init+0xcb/0x210 [nouveau]
> > >  nvkm_subdev_init+0xd6/0x230 [nouveau]
> > >  nvkm_engine_ref.part.0+0x52/0x70 [nouveau]
> > >  nvkm_engine_ref+0x13/0x20 [nouveau]
> > >  nvkm_ioctl_new+0x12c/0x260 [nouveau]
> > >  ? nvkm_fifo_chan_child_del+0xa0/0xa0 [nouveau]
> > >  ? gf100_gr_dtor+0xe0/0xe0 [nouveau]
> > >  nvkm_ioctl+0xe2/0x180 [nouveau]
> > >  nvkm_client_ioctl+0x12/0x20 [nouveau]
> > >  nvif_object_ioctl+0x47/0x50 [nouveau]
> > >  nvif_object_init+0xc8/0x120 [nouveau]
> > >  nvc0_fbcon_accel_init+0x5c/0x960 [nouveau]
> > >  nouveau_fbcon_create+0x5a5/0x5d0 [nouveau]
> > >  ? drm_setup_crtcs+0x27b/0xcb0 [drm_kms_helper]
> > >  ? __lock_is_held+0x5e/0xa0
> > >  __drm_fb_helper_initial_config_and_unlock+0x27c/0x520 [drm_kms_helper]
> > >  drm_fb_helper_hotplug_event.part.29+0xae/0xc0 [drm_kms_helper]
> > >  drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper]
> > >  nouveau_fbcon_output_poll_changed+0xb8/0x110 [nouveau]
> > >  drm_kms_helper_hotplug_event+0x2a/0x40 [drm_kms_helper]
> > >  drm_dp_send_link_address+0x176/0x1c0 [drm_kms_helper]
> > >  drm_dp_check_and_send_link_address+0xa0/0xb0 [drm_kms_helper]
> > >  drm_dp_mst_link_probe_work+0xa4/0xc0 [drm_kms_helper]
> > >  process_one_work+0x22f/0x5c0
> > >  worker_thread+0x44/0x3a0
> > >  kthread+0x12b/0x150
> > >  ? wq_pool_ids_show+0x140/0x140
> > >  ? kthread_create_on_node+0x60/0x60
> > >  ret_from_fork+0x3a/0x50
> > > irq event stamp: 22490
> > > hardirqs last  enabled at (22489): [<ffffffff8113281d>]
> > > console_unlock+0x44d/0x5f0
> > > hardirqs last disabled at (22490): [<ffffffff81001c03>]
> > > trace_hardirqs_off_thunk+0x1a/0x1c
> > > softirqs last  enabled at (22486): [<ffffffff81c00330>]
> > > __do_softirq+0x330/0x44d
> > > softirqs last disabled at (22479): [<ffffffff810c3105>]
> > > irq_exit+0xe5/0xf0
> > > WARNING: CPU: 0 PID: 12 at
> > > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > ---[ end trace bf0976ed88b122a8 ]---
> > > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy:
> > > 1)
> > > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0, busy:
> > > 1)
> > > nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 0000000000008000 engine
> > > 00 [GR] client 15 [HUB/SCC_NB] reason c4 [] on channel -1 [0000000000
> > > unknown]
> > > 
> > > From which the GPU never manages to recover. Booting without nouveau
> > > loading causes issues as well, since the GPU starts sending spurious
> > > interrupts that cause other device's IRQs to get disabled by the kernel:
> > > 
> > > irq 16: nobody cared (try booting with the "irqpoll" option)
> > > …
> > > handlers:
> > > [<000000007faa9e99>] i801_isr [i2c_i801]
> > > Disabling IRQ #16
> > > …
> > > serio: RMI4 PS/2 pass-through port at rmi4-00.fn03
> > > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > > i801_smbus 0000:00:1f.4: Transaction timeout
> > > rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX
> > > register (-110).
> > > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > > i801_smbus 0000:00:1f.4: Transaction timeout
> > > rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change enabled
> > > interrupts!
> > > 
> > > Which in turn causes the touchpad and sometimes even other things to get
> > > disabled.
> > > 
> > > Since the GPU staying on causes problems even without nouveau's
> > > intervention, we can't fix this problem from nouveau itself. We have to
> > > fix it as early as possible in the boot sequence in order to make sure
> > > that the GPU is in a clean state before it has a chance to spam us with
> > > interrupts and break things.
> > 
> > Was nouveau loaded *before* the reboot?  Or can you reproduce the
> > spurious interrupts even if you do a cold reboot without nouveau, then
> > a warm reboot again without nouveau?
> 
> Nouveau was loaded before the reboot, yes, and as far as I'm aware this
> bug won't show up following the steps you described here. We wouldn't
> really notice the interrupts if this bug happened without nouveau loaded
> (since the BIOS doesn't arm them). However, I can confirm it's being
> reset each on each warm reboot when nouveau's completely disabled by
> sticking values into some MMIO registers we know the VBIOS doesn't touch
> followed by rebooting in order to see if they retain their value (this
> is how I discovered that the GPU wasn't being power cycled in the first
> place, if the values I stick into said registers gets cleared after
> reboot then the GPU was reset, otherwise it wasn't).
> 
> 
> > > So to do this, we add a new pci quirk using
> > > DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
> > > at boot finishes. From there, we check to make sure that this is indeed
> > > the specific P50 variant of this GPU. We also make sure that the GPU PCI
> > > device is advertising NoReset- in order to prevent us from trying to
> > > reset the GPU when the machine is in Dedicated graphics mode (where the
> > > GPU being initialized by the BIOS is normal and expected). Finally, we
> > > try mapping the MMIO space for the GPU which should only work if the GPU
> > > is actually active in D0 mode. We can then read the magic 0x2240c
> > > register on the GPU, which will have bit 1 set if the GPU's firmware has
> > > already been posted during a previous boot. Once we've confirmed all of
> > > this, we reset the PCI device and re-disable it - bringing the GPU back
> > > into a healthy state.
> > > 
> > > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > > Cc: nouveau@lists.freedesktop.org
> > > Cc: dri-devel@lists.freedesktop.org
> > > Cc: Karol Herbst <kherbst@redhat.com>
> > > Cc: Ben Skeggs <skeggsb@gmail.com>
> > > Cc: stable@vger.kernel.org
> > > ---
> > >  drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 65 insertions(+)
> > > 
> > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > > index b0a413f3f7ca..948492fda8bf 100644
> > > --- a/drivers/pci/quirks.c
> > > +++ b/drivers/pci/quirks.c
> > > @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
> > >  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
> > >  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
> > >  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> > > +
> > > +/*
> > > + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a
> > > Nvidia
> > > + * Quadro M1000M, the BIOS will occasionally make the mistake of not
> > > resetting
> > > + * the nvidia GPU between reboots if the system is configured to use
> > > hybrid
> > > + * graphics mode. This results in the GPU being left in whatever state
> > > it
> > > was
> > > + * in during the previous boot which causes spurious interrupts from
> > > the
> > > GPU,
> > > + * which in turn cause us to disable the wrong IRQs and end up breaking
> > > the
> > > + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> > > + *
> > > + * Luckily, it seems a simple reset of the PCI device for the nvidia
> > > GPU
> > > + * manages to bring the GPU back into a clean state and fix all of
> > > these
> > > + * issues. Additionally since the GPU will report NoReset+ when the
> > > machine is
> > > + * configured in Dedicated display mode, we don't need to worry about
> > > + * accidentally resetting the GPU when it's supposed to already be
> > > + * initialized.
> > > + */
> > > +static void
> > > +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> > > +{
> > > +	void __iomem *map;
> > > +	int ret;
> > > +
> > > +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> > > +	    pdev->subsystem_device != 0x222e ||
> > > +	    !pdev->reset_fn)
> > > +		return;
> > > +
> > > +	/*
> > > +	 * If we can't enable the device's mmio space, it's probably not even
> > > +	 * initialized. This is fine, and means we can just skip the quirk
> > > +	 * entirely.
> > > +	 */
> > > +	if (pci_enable_device_mem(pdev)) {
> > > +		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
> > > +		return;
> > > +	}
> > > +
> > > +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> > > +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> > > +	if (!map) {
> > > +		pci_err(pdev, "Can't map MMIO space, this is probably very
> > > bad\n");
> > > +		goto out_disable;
> > > +	}
> > > +
> > > +	/*
> > > +	 * Be extra careful, and make sure that the GPU firmware is posted
> > > +	 * before trying a reset
> > > +	 */
> > > +	if (ioread32(map + 0x2240c) & 0x2) {
> > > +		pci_info(pdev,
> > > +			 FW_BUG "GPU left initialized by EFI, resetting\n");
> > > +		ret = pci_reset_function(pdev);
> > > +		if (ret < 0)
> > > +			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
> > > +	}
> > > +
> > > +	iounmap(map);
> > > +out_disable:
> > > +	pci_disable_device(pdev);
> > > +}
> > > +
> > > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> > > +			      PCI_CLASS_DISPLAY_VGA, 8,
> > > +			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot)
> > > ;
> > > -- 
> > > 2.20.1
> > >
Bump, sorry to bug you but is there any update on this or any information you
still need from me which would help get this upstream?

On Wed, 2019-03-13 at 18:25 -0400, Lyude Paul wrote:
> [note to David Ober: you -should- be able to reply to this, hopefully, but I
> haven't actually tested that so results may vary]
> 
> Hi again! Sorry I didn't fully answer all of the questions you originally
> asked in this email, I had to get in contact with Lenovo to make sure that
> it
> was OK for me to disclose more details on this bug (and I had PTO scheduled
> immediately after I asked). I've added David Ober from Lenovo to this thread
> as well. So now that I've got Lenovo's approval I can answer those
> questions,
> and give some better answers for the others! (see below)
> 
> 
> On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > > Hi Lyude,
> > > 
> > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > > On a very specific subset of ThinkPad P50 SKUs, particularly ones that
> > > > come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
> > > > seems to have a very nasty habit of not always resetting the secondary
> > > > Nvidia GPU between full reboots if the laptop is configured in Hybrid
> > > > Graphics mode. The reason for this happening is unknown, but the
> > > > following steps and possibly a good bit of patience will reproduce the
> > > > issue:
> > > > 
> > > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may
> > > > help)
> > > > 4. If nouveau loads up properly, reboot the machine again and go back
> > > > to
> > > > step 2 until you reproduce the issue
> > > > 
> > > > This results in some very strange behavior: the GPU will
> > > > quite literally be left in exactly the same state it was in when the
> > > > previously booted kernel started the reboot. This has all sorts of bad
> > > > sideaffects: for starters, this completely breaks nouveau starting
> > > > with
> > > > a
> > > > mysterious EVO channel failure that happens well before we've actually
> > > > used the EVO channel for anything:
> > > 
> > > There are a lot of moving parts here that are probably obvious to you
> > > but not to me.  I need help untangling this a bit so I'm comfortable
> > > that we got to the root cause and that we're doing something logical
> > > as opposed to something that just happens to make things work.  I
> > > really don't know enough to even ask the right questions...
> > 
> > I completely understand! I'm pretty sure I'd be just as skeptical if I was
> > in
> > your position reviewing a patch like this :P
> > 
> > > Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
> > > including "lspci -vvxxx" and dmidecode for the system.
> > > 
> > Not yet, but there has been discussion about this between nouveau
> > developers
> > on our IRC channel.
> I lied: yes there actually is a bug report for this, but it's currently on
> the
> Red Hat bugzilla. I can get more information from it if you need (with
> lenovo's approval of course).
> 
> > > Is this running a current BIOS?  The date in your log below looks
> > > pretty recent, so I assume it is current.
> > 
> > Yes, this is the most up to date BIOS available for this system.
> 
> And additionally: I've been working with Lenovo on this issue for a couple
> of
> months now, and we've gone through dozens of different trial BIOSes with no
> success thus far. However, Lenovo is currently working on trying to add this
> workaround into their BIOS but I've been told that this change is going to
> take a decent amount of time since they need to test it across multiple
> operating systems. I'd be happy to come back and add a conditional later to
> turn this workaround off for later BIOS versions once Lenovo has released a
> proper fix.
> 
> With all of that being said, [how] do you think we should proceed?
> 
> > > I assume "hybrid graphics" means you have two GPUs.  Do you select
> > > hybrid graphics mode in the BIOS?
> > 
> > Yes, the P50 has two available modes in the BIOS: Dedicated (e.g. only
> > the nvidia GPU is used for everything), and Hybrid (i915 drives the
> > built-in display panel, nouveau drives everything else). This bug only
> > seems to occur in Hybrid mode.
> > 
> > > I assume when you say the Nvidia GPU doesn't get reset on a full
> > > reboot, you're talking about a "warm reboot", and that if you actually
> > > remove the power and do a cold reboot, there's no problem?
> > 
> > If you meant "unplugging the power adapter" when you said cutting the
> > power we don't need to go that far, but shutting down the machine and
> > restarting it by hand does avoid the problem yes.
> > 
> > > I assume Nvidia GPU being active means you are using the performance
> > > GPU.  Does that mean the integrated GPU is completely unused and Linux
> > > does nothing at all with it?  Is Linux doing any switching between
> > > them?  If so, how?  I am not 100% confident in the code I've seen that
> > > does the switching.
> > 
> > "Switching" isn't really the right word to describe it these days as the
> > process for how this is handled has changed quite a bit in the last few
> > years. As I mentioned above, the main intel GPU is used for driving the
> > built-in display. As for the nvidia GPU, it's used to drive any kind of
> > external displays connected to the P50 and can also be used to do
> > rendering through DRI PRIME. The connector hookups are mostly hardcoded
> > as there isn't really much of a mux, unlike the old days where we could
> > actually do things like switch which GPU was driving the internal
> > display on the fly with  vga-switcheroo using the _DSM methods provided
> > by ACPI.
> > 
> > Nowadays muxless laptops like the ThinkPad P50 don't make much use of
> > _DSM for power management and instead just runtime suspend the dedicated
> > nvidia GPU when it's not in use. We rely on the PCI subsystem to invoke
> > the _PR3 ACPI methods for suspending and resuming the GPU and don't
> > handle much of it ourselves anymore:
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/nouveau/nouveau_drm.c?h=v5.0-rc6#n860
> > 
> > (You can ignore the call to nouveau_switcheroo_optimus_dsm() there; it
> >  doesn't do anything on systems like the P50 where we detect _PR3)
> > 
> > Additionally-if you see any problems with how we're handling things
> > there we're all ears! We've been trying to fix as many issues with
> > runtime PM as we can find.
> > 
> > Something else to consider here too: I've only ever managed to reproduce
> > this issue on this specific P50 SKU. Since I work on Desktop engineering
> > at Red Hat we have access to a very large number of laptops with hybrid
> > GPU setups. Interestingly I haven't ever reproduced anything like this
> > on any of them, even P50 SKUs with the M2000M GPU instead of the M1000M
> > (which are almost identical, they're both GM107 chips) I can follow the
> > same steps that I followed to reproduce this bug and it never appears.
> > 
> > Another thing to note: this bug also doesn't appear to happen 100% of
> > the time. Some warm reboots the GPU will be reset by the BIOS perfectly
> > fine.
> > 
> > > > nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
> > > > 00000002
> > > > 
> > > > Later on, this causes us to timeout trying to bring up the GR ctx:
> > > > 
> > > > ------------[ cut here ]------------
> > > > nouveau 0000:01:00.0: timeout
> > > > WARNING: CPU: 0 PID: 12 at
> > > > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > > > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > > Modules linked in: nouveau mxm_wmi i915 crc32c_intel ttm i2c_algo_bit
> > > > serio_raw drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
> > > > xhci_pci drm xhci_hcd i2c_core wmi video
> > > > CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.0.0-rc5Lyude-Test+ #29
> > > > Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET82W (1.55 )
> > > > 12/18/2018
> > > > Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
> > > > RIP: 0010:gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > > Code: 85 d2 75 04 48 8b 57 10 48 89 95 28 ff ff ff e8 b4 37 0e e1 48
> > > > 8b
> > > > 95 28 ff ff ff 48 c7 c7 b1 97 57 a0 48 89 c6 e8 5a 38 c0 e0 <0f> 0b e9
> > > > b9 fd ff ff 48 8b 85 60 ff ff ff 48 8b 40 10 48 8b 78 10
> > > > RSP: 0018:ffffc900000b77f0 EFLAGS: 00010286
> > > > RAX: 0000000000000000 RBX: ffff888871af8000 RCX: 0000000000000000
> > > > RDX: ffff88887f41dfe0 RSI: ffff88887f415698 RDI: ffff88887f415698
> > > > RBP: ffffc900000b78c8 R08: 0000000000000000 R09: 0000000000000000
> > > > R10: 0000000000000000 R11: 0000000000000000 R12: ffff888872118000
> > > > R13: 0000000000000000 R14: ffffffffa0551420 R15: ffffc900000b7818
> > > > FS:  0000000000000000(0000) GS:ffff88887f400000(0000)
> > > > knlGS:0000000000000000
> > > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > > CR2: 00005644d0556ca8 CR3: 0000000002214006 CR4: 00000000003606f0
> > > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > > Call Trace:
> > > >  gf100_gr_init_ctxctl+0x27b/0x2d0 [nouveau]
> > > >  gf100_gr_init+0x5bd/0x5e0 [nouveau]
> > > >  gf100_gr_init_+0x61/0x70 [nouveau]
> > > >  nvkm_gr_init+0x1d/0x20 [nouveau]
> > > >  nvkm_engine_init+0xcb/0x210 [nouveau]
> > > >  nvkm_subdev_init+0xd6/0x230 [nouveau]
> > > >  nvkm_engine_ref.part.0+0x52/0x70 [nouveau]
> > > >  nvkm_engine_ref+0x13/0x20 [nouveau]
> > > >  nvkm_ioctl_new+0x12c/0x260 [nouveau]
> > > >  ? nvkm_fifo_chan_child_del+0xa0/0xa0 [nouveau]
> > > >  ? gf100_gr_dtor+0xe0/0xe0 [nouveau]
> > > >  nvkm_ioctl+0xe2/0x180 [nouveau]
> > > >  nvkm_client_ioctl+0x12/0x20 [nouveau]
> > > >  nvif_object_ioctl+0x47/0x50 [nouveau]
> > > >  nvif_object_init+0xc8/0x120 [nouveau]
> > > >  nvc0_fbcon_accel_init+0x5c/0x960 [nouveau]
> > > >  nouveau_fbcon_create+0x5a5/0x5d0 [nouveau]
> > > >  ? drm_setup_crtcs+0x27b/0xcb0 [drm_kms_helper]
> > > >  ? __lock_is_held+0x5e/0xa0
> > > >  __drm_fb_helper_initial_config_and_unlock+0x27c/0x520
> > > > [drm_kms_helper]
> > > >  drm_fb_helper_hotplug_event.part.29+0xae/0xc0 [drm_kms_helper]
> > > >  drm_fb_helper_hotplug_event+0x1c/0x30 [drm_kms_helper]
> > > >  nouveau_fbcon_output_poll_changed+0xb8/0x110 [nouveau]
> > > >  drm_kms_helper_hotplug_event+0x2a/0x40 [drm_kms_helper]
> > > >  drm_dp_send_link_address+0x176/0x1c0 [drm_kms_helper]
> > > >  drm_dp_check_and_send_link_address+0xa0/0xb0 [drm_kms_helper]
> > > >  drm_dp_mst_link_probe_work+0xa4/0xc0 [drm_kms_helper]
> > > >  process_one_work+0x22f/0x5c0
> > > >  worker_thread+0x44/0x3a0
> > > >  kthread+0x12b/0x150
> > > >  ? wq_pool_ids_show+0x140/0x140
> > > >  ? kthread_create_on_node+0x60/0x60
> > > >  ret_from_fork+0x3a/0x50
> > > > irq event stamp: 22490
> > > > hardirqs last  enabled at (22489): [<ffffffff8113281d>]
> > > > console_unlock+0x44d/0x5f0
> > > > hardirqs last disabled at (22490): [<ffffffff81001c03>]
> > > > trace_hardirqs_off_thunk+0x1a/0x1c
> > > > softirqs last  enabled at (22486): [<ffffffff81c00330>]
> > > > __do_softirq+0x330/0x44d
> > > > softirqs last disabled at (22479): [<ffffffff810c3105>]
> > > > irq_exit+0xe5/0xf0
> > > > WARNING: CPU: 0 PID: 12 at
> > > > drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c:1547
> > > > gf100_grctx_generate+0x7b2/0x850 [nouveau]
> > > > ---[ end trace bf0976ed88b122a8 ]---
> > > > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0,
> > > > busy:
> > > > 1)
> > > > nouveau 0000:01:00.0: gr: wait for idle timeout (en: 1, ctxsw: 0,
> > > > busy:
> > > > 1)
> > > > nouveau 0000:01:00.0: fifo: fault 01 [WRITE] at 0000000000008000
> > > > engine
> > > > 00 [GR] client 15 [HUB/SCC_NB] reason c4 [] on channel -1 [0000000000
> > > > unknown]
> > > > 
> > > > From which the GPU never manages to recover. Booting without nouveau
> > > > loading causes issues as well, since the GPU starts sending spurious
> > > > interrupts that cause other device's IRQs to get disabled by the
> > > > kernel:
> > > > 
> > > > irq 16: nobody cared (try booting with the "irqpoll" option)
> > > > …
> > > > handlers:
> > > > [<000000007faa9e99>] i801_isr [i2c_i801]
> > > > Disabling IRQ #16
> > > > …
> > > > serio: RMI4 PS/2 pass-through port at rmi4-00.fn03
> > > > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > > > i801_smbus 0000:00:1f.4: Transaction timeout
> > > > rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX
> > > > register (-110).
> > > > i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
> > > > i801_smbus 0000:00:1f.4: Transaction timeout
> > > > rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change
> > > > enabled
> > > > interrupts!
> > > > 
> > > > Which in turn causes the touchpad and sometimes even other things to
> > > > get
> > > > disabled.
> > > > 
> > > > Since the GPU staying on causes problems even without nouveau's
> > > > intervention, we can't fix this problem from nouveau itself. We have
> > > > to
> > > > fix it as early as possible in the boot sequence in order to make sure
> > > > that the GPU is in a clean state before it has a chance to spam us
> > > > with
> > > > interrupts and break things.
> > > 
> > > Was nouveau loaded *before* the reboot?  Or can you reproduce the
> > > spurious interrupts even if you do a cold reboot without nouveau, then
> > > a warm reboot again without nouveau?
> > 
> > Nouveau was loaded before the reboot, yes, and as far as I'm aware this
> > bug won't show up following the steps you described here. We wouldn't
> > really notice the interrupts if this bug happened without nouveau loaded
> > (since the BIOS doesn't arm them). However, I can confirm it's being
> > reset each on each warm reboot when nouveau's completely disabled by
> > sticking values into some MMIO registers we know the VBIOS doesn't touch
> > followed by rebooting in order to see if they retain their value (this
> > is how I discovered that the GPU wasn't being power cycled in the first
> > place, if the values I stick into said registers gets cleared after
> > reboot then the GPU was reset, otherwise it wasn't).
> > 
> > 
> > > > So to do this, we add a new pci quirk using
> > > > DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI
> > > > probe
> > > > at boot finishes. From there, we check to make sure that this is
> > > > indeed
> > > > the specific P50 variant of this GPU. We also make sure that the GPU
> > > > PCI
> > > > device is advertising NoReset- in order to prevent us from trying to
> > > > reset the GPU when the machine is in Dedicated graphics mode (where
> > > > the
> > > > GPU being initialized by the BIOS is normal and expected). Finally, we
> > > > try mapping the MMIO space for the GPU which should only work if the
> > > > GPU
> > > > is actually active in D0 mode. We can then read the magic 0x2240c
> > > > register on the GPU, which will have bit 1 set if the GPU's firmware
> > > > has
> > > > already been posted during a previous boot. Once we've confirmed all
> > > > of
> > > > this, we reset the PCI device and re-disable it - bringing the GPU
> > > > back
> > > > into a healthy state.
> > > > 
> > > > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > > > Cc: nouveau@lists.freedesktop.org
> > > > Cc: dri-devel@lists.freedesktop.org
> > > > Cc: Karol Herbst <kherbst@redhat.com>
> > > > Cc: Ben Skeggs <skeggsb@gmail.com>
> > > > Cc: stable@vger.kernel.org
> > > > ---
> > > >  drivers/pci/quirks.c | 65
> > > > ++++++++++++++++++++++++++++++++++++++++++++
> > > >  1 file changed, 65 insertions(+)
> > > > 
> > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > > > index b0a413f3f7ca..948492fda8bf 100644
> > > > --- a/drivers/pci/quirks.c
> > > > +++ b/drivers/pci/quirks.c
> > > > @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
> > > >  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
> > > >  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
> > > >  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> > > > +
> > > > +/*
> > > > + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a
> > > > Nvidia
> > > > + * Quadro M1000M, the BIOS will occasionally make the mistake of not
> > > > resetting
> > > > + * the nvidia GPU between reboots if the system is configured to use
> > > > hybrid
> > > > + * graphics mode. This results in the GPU being left in whatever
> > > > state
> > > > it
> > > > was
> > > > + * in during the previous boot which causes spurious interrupts from
> > > > the
> > > > GPU,
> > > > + * which in turn cause us to disable the wrong IRQs and end up
> > > > breaking
> > > > the
> > > > + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> > > > + *
> > > > + * Luckily, it seems a simple reset of the PCI device for the nvidia
> > > > GPU
> > > > + * manages to bring the GPU back into a clean state and fix all of
> > > > these
> > > > + * issues. Additionally since the GPU will report NoReset+ when the
> > > > machine is
> > > > + * configured in Dedicated display mode, we don't need to worry about
> > > > + * accidentally resetting the GPU when it's supposed to already be
> > > > + * initialized.
> > > > + */
> > > > +static void
> > > > +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> > > > +{
> > > > +	void __iomem *map;
> > > > +	int ret;
> > > > +
> > > > +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> > > > +	    pdev->subsystem_device != 0x222e ||
> > > > +	    !pdev->reset_fn)
> > > > +		return;
> > > > +
> > > > +	/*
> > > > +	 * If we can't enable the device's mmio space, it's probably
> > > > not even
> > > > +	 * initialized. This is fine, and means we can just skip the
> > > > quirk
> > > > +	 * entirely.
> > > > +	 */
> > > > +	if (pci_enable_device_mem(pdev)) {
> > > > +		pci_dbg(pdev, "Can't enable device mem, no reset
> > > > needed\n");
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> > > > +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> > > > +	if (!map) {
> > > > +		pci_err(pdev, "Can't map MMIO space, this is probably
> > > > very
> > > > bad\n");
> > > > +		goto out_disable;
> > > > +	}
> > > > +
> > > > +	/*
> > > > +	 * Be extra careful, and make sure that the GPU firmware is
> > > > posted
> > > > +	 * before trying a reset
> > > > +	 */
> > > > +	if (ioread32(map + 0x2240c) & 0x2) {
> > > > +		pci_info(pdev,
> > > > +			 FW_BUG "GPU left initialized by EFI,
> > > > resetting\n");
> > > > +		ret = pci_reset_function(pdev);
> > > > +		if (ret < 0)
> > > > +			pci_err(pdev, "Failed to reset GPU: %d\n",
> > > > ret);
> > > > +	}
> > > > +
> > > > +	iounmap(map);
> > > > +out_disable:
> > > > +	pci_disable_device(pdev);
> > > > +}
> > > > +
> > > > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> > > > +			      PCI_CLASS_DISPLAY_VGA, 8,
> > > > +			      quirk_lenovo_thinkpad_p50_nvgpu_survives
> > > > _reboot)
> > > > ;
> > > > -- 
> > > > 2.20.1
> > > >
[+cc Rafael]

On Wed, Mar 13, 2019 at 06:25:02PM -0400, Lyude Paul wrote:
> On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > > On a very specific subset of ThinkPad P50 SKUs, particularly
> > > > ones that come with a Quadro M1000M chip instead of the M2000M
> > > > variant, the BIOS seems to have a very nasty habit of not
> > > > always resetting the secondary Nvidia GPU between full reboots
> > > > if the laptop is configured in Hybrid Graphics mode. The
> > > > reason for this happening is unknown, but the following steps
> > > > and possibly a good bit of patience will reproduce the issue:
> > > > 
> > > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> > > > 4. If nouveau loads up properly, reboot the machine again and go back to
> > > > step 2 until you reproduce the issue
> > > > 
> > > > This results in some very strange behavior: the GPU will quite
> > > > literally be left in exactly the same state it was in when the
> > > > previously booted kernel started the reboot. This has all
> > > > sorts of bad sideaffects: for starters, this completely breaks
> > > > nouveau starting with a mysterious EVO channel failure that
> > > > happens well before we've actually used the EVO channel for
> > > > anything:

Thanks for the hybrid tutorial (snipped from this response).  IIUC,
what you said was that in hybrid mode, the Intel GPU drives the
built-in display and the Nvidia GPU drives any external displays and
may be used for DRI PRIME rendering (whatever that is).  But since you
say the Nvidia device gets runtime suspended, I assume there's no
external display here and you're not using DRI PRIME.

I wonder if it's related to the fact that the Nvidia GPU has been
runtime suspended before you do the reboot.  Can you try turning of
runtime power management for the GPU by setting the runpm module
parameter to 0?  I *think* this would be booting with
"nouveau.runpm=0".

> > > Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
> > > including "lspci -vvxxx" and dmidecode for the system.
> > > 
> > Not yet, but there has been discussion about this between nouveau
> > developers on our IRC channel.
>
> I lied: yes there actually is a bug report for this, but it's
> currently on the Red Hat bugzilla. I can get more information from
> it if you need (with lenovo's approval of course).

Can you please make a bugzilla.kernel.org entry with as much
information (dmesg, "lspci -vvxxx", dmidecode, etc) as you can get
approval for?  You can include the Red Hat bugzilla URL in the commit
log, too, but that's not quite as good because we have no control over
whether it's public.

> And additionally: I've been working with Lenovo on this issue for a
> couple of months now, and we've gone through dozens of different
> trial BIOSes with no success thus far. However, Lenovo is currently
> working on trying to add this workaround into their BIOS but I've
> been told that this change is going to take a decent amount of time
> since they need to test it across multiple operating systems. I'd be
> happy to come back and add a conditional later to turn this
> workaround off for later BIOS versions once Lenovo has released a
> proper fix.

Sounds like Lenovo is going to a lot of trouble for this.  The ideal
thing from my point of view would be if they could figure out why this
works on Windows but not on Linux.  I doubt Windows has a quirk like
this, so if we could figure out why it works on Windows, we could
likely do something similar in Linux.

> > > > So to do this, we add a new pci quirk using
> > > > DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
> > > > at boot finishes. From there, we check to make sure that this is indeed
> > > > the specific P50 variant of this GPU. We also make sure that the GPU PCI
> > > > device is advertising NoReset- in order to prevent us from trying to
> > > > reset the GPU when the machine is in Dedicated graphics mode (where the
> > > > GPU being initialized by the BIOS is normal and expected). Finally, we
> > > > try mapping the MMIO space for the GPU which should only work if the GPU
> > > > is actually active in D0 mode. We can then read the magic 0x2240c
> > > > register on the GPU, which will have bit 1 set if the GPU's firmware has
> > > > already been posted during a previous boot. Once we've confirmed all of
> > > > this, we reset the PCI device and re-disable it - bringing the GPU back
> > > > into a healthy state.
> > > > 
> > > > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > > > Cc: nouveau@lists.freedesktop.org
> > > > Cc: dri-devel@lists.freedesktop.org
> > > > Cc: Karol Herbst <kherbst@redhat.com>
> > > > Cc: Ben Skeggs <skeggsb@gmail.com>
> > > > Cc: stable@vger.kernel.org
> > > > ---
> > > >  drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
> > > >  1 file changed, 65 insertions(+)
> > > > 
> > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > > > index b0a413f3f7ca..948492fda8bf 100644
> > > > --- a/drivers/pci/quirks.c
> > > > +++ b/drivers/pci/quirks.c
> > > > @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
> > > >  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
> > > >  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
> > > >  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> > > > +
> > > > +/*
> > > > + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a
> > > > Nvidia
> > > > + * Quadro M1000M, the BIOS will occasionally make the mistake of not
> > > > resetting
> > > > + * the nvidia GPU between reboots if the system is configured to use
> > > > hybrid
> > > > + * graphics mode. This results in the GPU being left in whatever state
> > > > it
> > > > was
> > > > + * in during the previous boot which causes spurious interrupts from
> > > > the
> > > > GPU,
> > > > + * which in turn cause us to disable the wrong IRQs and end up breaking
> > > > the
> > > > + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> > > > + *
> > > > + * Luckily, it seems a simple reset of the PCI device for the nvidia
> > > > GPU
> > > > + * manages to bring the GPU back into a clean state and fix all of
> > > > these
> > > > + * issues. Additionally since the GPU will report NoReset+ when the
> > > > machine is
> > > > + * configured in Dedicated display mode, we don't need to worry about
> > > > + * accidentally resetting the GPU when it's supposed to already be
> > > > + * initialized.
> > > > + */
> > > > +static void
> > > > +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> > > > +{
> > > > +	void __iomem *map;
> > > > +	int ret;
> > > > +
> > > > +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> > > > +	    pdev->subsystem_device != 0x222e ||
> > > > +	    !pdev->reset_fn)
> > > > +		return;
> > > > +
> > > > +	/*
> > > > +	 * If we can't enable the device's mmio space, it's probably not even
> > > > +	 * initialized. This is fine, and means we can just skip the quirk
> > > > +	 * entirely.
> > > > +	 */
> > > > +	if (pci_enable_device_mem(pdev)) {
> > > > +		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
> > > > +		return;
> > > > +	}
> > > > +
> > > > +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> > > > +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> > > > +	if (!map) {
> > > > +		pci_err(pdev, "Can't map MMIO space, this is probably very
> > > > bad\n");
> > > > +		goto out_disable;
> > > > +	}
> > > > +
> > > > +	/*
> > > > +	 * Be extra careful, and make sure that the GPU firmware is posted
> > > > +	 * before trying a reset
> > > > +	 */
> > > > +	if (ioread32(map + 0x2240c) & 0x2) {
> > > > +		pci_info(pdev,
> > > > +			 FW_BUG "GPU left initialized by EFI, resetting\n");
> > > > +		ret = pci_reset_function(pdev);
> > > > +		if (ret < 0)
> > > > +			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
> > > > +	}
> > > > +
> > > > +	iounmap(map);
> > > > +out_disable:
> > > > +	pci_disable_device(pdev);
> > > > +}
> > > > +
> > > > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> > > > +			      PCI_CLASS_DISPLAY_VGA, 8,
> > > > +			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot)
> > > > ;
> > > > -- 
> > > > 2.20.1
> > > > 
> -- 
> Cheers,
> 	Lyude Paul
>
On Thu, Mar 21, 2019 at 05:48:19PM -0500, Bjorn Helgaas wrote:
> On Wed, Mar 13, 2019 at 06:25:02PM -0400, Lyude Paul wrote:
> > On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> > > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > > > On a very specific subset of ThinkPad P50 SKUs, particularly
> > > > > ones that come with a Quadro M1000M chip instead of the M2000M
> > > > > variant, the BIOS seems to have a very nasty habit of not
> > > > > always resetting the secondary Nvidia GPU between full reboots
> > > > > if the laptop is configured in Hybrid Graphics mode. The
> > > > > reason for this happening is unknown, but the following steps
> > > > > and possibly a good bit of patience will reproduce the issue:
> > > > > 
> > > > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> > > > > 4. If nouveau loads up properly, reboot the machine again and go back to
> > > > > step 2 until you reproduce the issue
> > > > > 
> > > > > This results in some very strange behavior: the GPU will quite
> > > > > literally be left in exactly the same state it was in when the
> > > > > previously booted kernel started the reboot. This has all
> > > > > sorts of bad sideaffects: for starters, this completely breaks
> > > > > nouveau starting with a mysterious EVO channel failure that
> > > > > happens well before we've actually used the EVO channel for
> > > > > anything:
> 
> Thanks for the hybrid tutorial (snipped from this response).  IIUC,
> what you said was that in hybrid mode, the Intel GPU drives the
> built-in display and the Nvidia GPU drives any external displays and
> may be used for DRI PRIME rendering (whatever that is).  But since you
> say the Nvidia device gets runtime suspended, I assume there's no
> external display here and you're not using DRI PRIME.
> 
> I wonder if it's related to the fact that the Nvidia GPU has been
> runtime suspended before you do the reboot.  Can you try turning of
> runtime power management for the GPU by setting the runpm module
> parameter to 0?  I *think* this would be booting with
> "nouveau.runpm=0".

Sorry, I wasn't really thinking here.  You already *said* this is
related to runtime suspend.  It only happens when the Nvidia GPU has
been suspended.

I don't know that much about suspend, but ISTR seeing comments about
resuming devices before we shutdown.  If we do that, maybe there's
some kind of race between that resume and the reboot?

Bjorn
Note: I did read your response lower down in the thread, but I wanted to make
sure I addressed one of the comments here (see below)

On Thu, 2019-03-21 at 17:48 -0500, Bjorn Helgaas wrote:
> [+cc Rafael]
> 
> On Wed, Mar 13, 2019 at 06:25:02PM -0400, Lyude Paul wrote:
> > On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> > > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > > > On a very specific subset of ThinkPad P50 SKUs, particularly
> > > > > ones that come with a Quadro M1000M chip instead of the M2000M
> > > > > variant, the BIOS seems to have a very nasty habit of not
> > > > > always resetting the secondary Nvidia GPU between full reboots
> > > > > if the laptop is configured in Hybrid Graphics mode. The
> > > > > reason for this happening is unknown, but the following steps
> > > > > and possibly a good bit of patience will reproduce the issue:
> > > > > 
> > > > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may
> > > > > help)
> > > > > 4. If nouveau loads up properly, reboot the machine again and go
> > > > > back to
> > > > > step 2 until you reproduce the issue
> > > > > 
> > > > > This results in some very strange behavior: the GPU will quite
> > > > > literally be left in exactly the same state it was in when the
> > > > > previously booted kernel started the reboot. This has all
> > > > > sorts of bad sideaffects: for starters, this completely breaks
> > > > > nouveau starting with a mysterious EVO channel failure that
> > > > > happens well before we've actually used the EVO channel for
> > > > > anything:
> 
> Thanks for the hybrid tutorial (snipped from this response).  IIUC,
> what you said was that in hybrid mode, the Intel GPU drives the
> built-in display and the Nvidia GPU drives any external displays and
> may be used for DRI PRIME rendering (whatever that is).  But since you
> say the Nvidia device gets runtime suspended, I assume there's no
> external display here and you're not using DRI PRIME.
> 
> I wonder if it's related to the fact that the Nvidia GPU has been
> runtime suspended before you do the reboot.  Can you try turning of
> runtime power management for the GPU by setting the runpm module
> parameter to 0?  I *think* this would be booting with
> "nouveau.runpm=0".
> 
> > > > Is there a bug report for this?  Bugzilla.kernel.org would be ideal,
> > > > including "lspci -vvxxx" and dmidecode for the system.
> > > > 
> > > Not yet, but there has been discussion about this between nouveau
> > > developers on our IRC channel.
> > 
> > I lied: yes there actually is a bug report for this, but it's
> > currently on the Red Hat bugzilla. I can get more information from
> > it if you need (with lenovo's approval of course).
> 
> Can you please make a bugzilla.kernel.org entry with as much
> information (dmesg, "lspci -vvxxx", dmidecode, etc) as you can get
> approval for?  You can include the Red Hat bugzilla URL in the commit
> log, too, but that's not quite as good because we have no control over
> whether it's public.
> 
> > And additionally: I've been working with Lenovo on this issue for a
> > couple of months now, and we've gone through dozens of different
> > trial BIOSes with no success thus far. However, Lenovo is currently
> > working on trying to add this workaround into their BIOS but I've
> > been told that this change is going to take a decent amount of time
> > since they need to test it across multiple operating systems. I'd be
> > happy to come back and add a conditional later to turn this
> > workaround off for later BIOS versions once Lenovo has released a
> > proper fix.
> 
> Sounds like Lenovo is going to a lot of trouble for this.  The ideal
> thing from my point of view would be if they could figure out why this
> works on Windows but not on Linux.  I doubt Windows has a quirk like
> this, so if we could figure out why it works on Windows, we could
> likely do something similar in Linux.

I did actually try this route after first finding this bug, but unfortunately
from what I understand there isn't really much more Lenovo can do other then
give us a patched BIOS or look at their own BIOS to see if it's the cause. 

Anyway, went ahead and filed a bug with as much information as I could get my
hands on here (different email then the one I'm talking to you from): 
https://bugzilla.kernel.org/show_bug.cgi?id=203003

> 
> > > > > So to do this, we add a new pci quirk using
> > > > > DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI
> > > > > probe
> > > > > at boot finishes. From there, we check to make sure that this is
> > > > > indeed
> > > > > the specific P50 variant of this GPU. We also make sure that the GPU
> > > > > PCI
> > > > > device is advertising NoReset- in order to prevent us from trying to
> > > > > reset the GPU when the machine is in Dedicated graphics mode (where
> > > > > the
> > > > > GPU being initialized by the BIOS is normal and expected). Finally,
> > > > > we
> > > > > try mapping the MMIO space for the GPU which should only work if the
> > > > > GPU
> > > > > is actually active in D0 mode. We can then read the magic 0x2240c
> > > > > register on the GPU, which will have bit 1 set if the GPU's firmware
> > > > > has
> > > > > already been posted during a previous boot. Once we've confirmed all
> > > > > of
> > > > > this, we reset the PCI device and re-disable it - bringing the GPU
> > > > > back
> > > > > into a healthy state.
> > > > > 
> > > > > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > > > > Cc: nouveau@lists.freedesktop.org
> > > > > Cc: dri-devel@lists.freedesktop.org
> > > > > Cc: Karol Herbst <kherbst@redhat.com>
> > > > > Cc: Ben Skeggs <skeggsb@gmail.com>
> > > > > Cc: stable@vger.kernel.org
> > > > > ---
> > > > >  drivers/pci/quirks.c | 65
> > > > > ++++++++++++++++++++++++++++++++++++++++++++
> > > > >  1 file changed, 65 insertions(+)
> > > > > 
> > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > > > > index b0a413f3f7ca..948492fda8bf 100644
> > > > > --- a/drivers/pci/quirks.c
> > > > > +++ b/drivers/pci/quirks.c
> > > > > @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
> > > > >  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
> > > > >  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
> > > > >  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> > > > > +
> > > > > +/*
> > > > > + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a
> > > > > Nvidia
> > > > > + * Quadro M1000M, the BIOS will occasionally make the mistake of
> > > > > not
> > > > > resetting
> > > > > + * the nvidia GPU between reboots if the system is configured to
> > > > > use
> > > > > hybrid
> > > > > + * graphics mode. This results in the GPU being left in whatever
> > > > > state
> > > > > it
> > > > > was
> > > > > + * in during the previous boot which causes spurious interrupts
> > > > > from
> > > > > the
> > > > > GPU,
> > > > > + * which in turn cause us to disable the wrong IRQs and end up
> > > > > breaking
> > > > > the
> > > > > + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> > > > > + *
> > > > > + * Luckily, it seems a simple reset of the PCI device for the
> > > > > nvidia
> > > > > GPU
> > > > > + * manages to bring the GPU back into a clean state and fix all of
> > > > > these
> > > > > + * issues. Additionally since the GPU will report NoReset+ when the
> > > > > machine is
> > > > > + * configured in Dedicated display mode, we don't need to worry
> > > > > about
> > > > > + * accidentally resetting the GPU when it's supposed to already be
> > > > > + * initialized.
> > > > > + */
> > > > > +static void
> > > > > +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev
> > > > > *pdev)
> > > > > +{
> > > > > +	void __iomem *map;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> > > > > +	    pdev->subsystem_device != 0x222e ||
> > > > > +	    !pdev->reset_fn)
> > > > > +		return;
> > > > > +
> > > > > +	/*
> > > > > +	 * If we can't enable the device's mmio space, it's probably
> > > > > not even
> > > > > +	 * initialized. This is fine, and means we can just skip the
> > > > > quirk
> > > > > +	 * entirely.
> > > > > +	 */
> > > > > +	if (pci_enable_device_mem(pdev)) {
> > > > > +		pci_dbg(pdev, "Can't enable device mem, no reset
> > > > > needed\n");
> > > > > +		return;
> > > > > +	}
> > > > > +
> > > > > +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> > > > > +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> > > > > +	if (!map) {
> > > > > +		pci_err(pdev, "Can't map MMIO space, this is probably
> > > > > very
> > > > > bad\n");
> > > > > +		goto out_disable;
> > > > > +	}
> > > > > +
> > > > > +	/*
> > > > > +	 * Be extra careful, and make sure that the GPU firmware is
> > > > > posted
> > > > > +	 * before trying a reset
> > > > > +	 */
> > > > > +	if (ioread32(map + 0x2240c) & 0x2) {
> > > > > +		pci_info(pdev,
> > > > > +			 FW_BUG "GPU left initialized by EFI,
> > > > > resetting\n");
> > > > > +		ret = pci_reset_function(pdev);
> > > > > +		if (ret < 0)
> > > > > +			pci_err(pdev, "Failed to reset GPU: %d\n",
> > > > > ret);
> > > > > +	}
> > > > > +
> > > > > +	iounmap(map);
> > > > > +out_disable:
> > > > > +	pci_disable_device(pdev);
> > > > > +}
> > > > > +
> > > > > +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> > > > > +			      PCI_CLASS_DISPLAY_VGA, 8,
> > > > > +			      quirk_lenovo_thinkpad_p50_nvgpu_survives
> > > > > _reboot)
> > > > > ;
> > > > > -- 
> > > > > 2.20.1
> > > > > 
> > -- 
> > Cheers,
> > 	Lyude Paul
> >
Hi, any update on this/do you guys need any more information here? Would very
much like to get this upstream

On Fri, 2019-03-22 at 06:30 -0500, Bjorn Helgaas wrote:
> On Thu, Mar 21, 2019 at 05:48:19PM -0500, Bjorn Helgaas wrote:
> > On Wed, Mar 13, 2019 at 06:25:02PM -0400, Lyude Paul wrote:
> > > On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote:
> > > > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote:
> > > > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> > > > > > On a very specific subset of ThinkPad P50 SKUs, particularly
> > > > > > ones that come with a Quadro M1000M chip instead of the M2000M
> > > > > > variant, the BIOS seems to have a very nasty habit of not
> > > > > > always resetting the secondary Nvidia GPU between full reboots
> > > > > > if the laptop is configured in Hybrid Graphics mode. The
> > > > > > reason for this happening is unknown, but the following steps
> > > > > > and possibly a good bit of patience will reproduce the issue:
> > > > > > 
> > > > > > 1. Boot up the laptop normally in Hybrid graphics mode
> > > > > > 2. Make sure nouveau is loaded and that the GPU is awake
> > > > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle
> > > > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may
> > > > > > help)
> > > > > > 4. If nouveau loads up properly, reboot the machine again and go
> > > > > > back to
> > > > > > step 2 until you reproduce the issue
> > > > > > 
> > > > > > This results in some very strange behavior: the GPU will quite
> > > > > > literally be left in exactly the same state it was in when the
> > > > > > previously booted kernel started the reboot. This has all
> > > > > > sorts of bad sideaffects: for starters, this completely breaks
> > > > > > nouveau starting with a mysterious EVO channel failure that
> > > > > > happens well before we've actually used the EVO channel for
> > > > > > anything:
> > 
> > Thanks for the hybrid tutorial (snipped from this response).  IIUC,
> > what you said was that in hybrid mode, the Intel GPU drives the
> > built-in display and the Nvidia GPU drives any external displays and
> > may be used for DRI PRIME rendering (whatever that is).  But since you
> > say the Nvidia device gets runtime suspended, I assume there's no
> > external display here and you're not using DRI PRIME.
> > 
> > I wonder if it's related to the fact that the Nvidia GPU has been
> > runtime suspended before you do the reboot.  Can you try turning of
> > runtime power management for the GPU by setting the runpm module
> > parameter to 0?  I *think* this would be booting with
> > "nouveau.runpm=0".
> 
> Sorry, I wasn't really thinking here.  You already *said* this is
> related to runtime suspend.  It only happens when the Nvidia GPU has
> been suspended.
> 
> I don't know that much about suspend, but ISTR seeing comments about
> resuming devices before we shutdown.  If we do that, maybe there's
> some kind of race between that resume and the reboot?
> 
> Bjorn
On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote:
> On a very specific subset of ThinkPad P50 SKUs, particularly ones that
> come with a Quadro M1000M chip instead of the M2000M variant, the BIOS
> seems to have a very nasty habit of not always resetting the secondary
> Nvidia GPU between full reboots if the laptop is configured in Hybrid
> Graphics mode. The reason for this happening is unknown, but the
> following steps and possibly a good bit of patience will reproduce the
> issue:
> 
> 1. Boot up the laptop normally in Hybrid graphics mode
> 2. Make sure nouveau is loaded and that the GPU is awake
> 2. Allow the nvidia GPU to runtime suspend itself after being idle
> 3. Reboot the machine, the more sudden the better (e.g sysrq-b may help)
> 4. If nouveau loads up properly, reboot the machine again and go back to
> step 2 until you reproduce the issue
> 
> This results in some very strange behavior: the GPU will
> quite literally be left in exactly the same state it was in when the
> previously booted kernel started the reboot. This has all sorts of bad
> sideaffects: for starters, this completely breaks nouveau starting with a
> mysterious EVO channel failure that happens well before we've actually
> used the EVO channel for anything:
> 
> nouveau 0000:01:00.0: disp: chid 0 mthd 0000 data 00000400 00001000
> 00000002
> ...

> So to do this, we add a new pci quirk using
> DECLARE_PCI_FIXUP_CLASS_FINAL that will be invoked before the PCI probe
> at boot finishes. From there, we check to make sure that this is indeed
> the specific P50 variant of this GPU. We also make sure that the GPU PCI
> device is advertising NoReset- in order to prevent us from trying to
> reset the GPU when the machine is in Dedicated graphics mode (where the
> GPU being initialized by the BIOS is normal and expected). Finally, we
> try mapping the MMIO space for the GPU which should only work if the GPU
> is actually active in D0 mode. We can then read the magic 0x2240c
> register on the GPU, which will have bit 1 set if the GPU's firmware has
> already been posted during a previous boot. Once we've confirmed all of
> this, we reset the PCI device and re-disable it - bringing the GPU back
> into a healthy state.
> 
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: nouveau@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: Karol Herbst <kherbst@redhat.com>
> Cc: Ben Skeggs <skeggsb@gmail.com>
> Cc: stable@vger.kernel.org

Applied to pci/misc for v5.2, thanks!

> ---
>  drivers/pci/quirks.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b0a413f3f7ca..948492fda8bf 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5117,3 +5117,68 @@ SWITCHTEC_QUIRK(0x8573);  /* PFXI 48XG3 */
>  SWITCHTEC_QUIRK(0x8574);  /* PFXI 64XG3 */
>  SWITCHTEC_QUIRK(0x8575);  /* PFXI 80XG3 */
>  SWITCHTEC_QUIRK(0x8576);  /* PFXI 96XG3 */
> +
> +/*
> + * On certain Lenovo Thinkpad P50 SKUs, specifically those with a Nvidia
> + * Quadro M1000M, the BIOS will occasionally make the mistake of not resetting
> + * the nvidia GPU between reboots if the system is configured to use hybrid
> + * graphics mode. This results in the GPU being left in whatever state it was
> + * in during the previous boot which causes spurious interrupts from the GPU,
> + * which in turn cause us to disable the wrong IRQs and end up breaking the
> + * touchpad. Unsurprisingly, this also completely breaks nouveau.
> + *
> + * Luckily, it seems a simple reset of the PCI device for the nvidia GPU
> + * manages to bring the GPU back into a clean state and fix all of these
> + * issues. Additionally since the GPU will report NoReset+ when the machine is
> + * configured in Dedicated display mode, we don't need to worry about
> + * accidentally resetting the GPU when it's supposed to already be
> + * initialized.
> + */
> +static void
> +quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot(struct pci_dev *pdev)
> +{
> +	void __iomem *map;
> +	int ret;
> +
> +	if (pdev->subsystem_vendor != PCI_VENDOR_ID_LENOVO ||
> +	    pdev->subsystem_device != 0x222e ||
> +	    !pdev->reset_fn)
> +		return;
> +
> +	/*
> +	 * If we can't enable the device's mmio space, it's probably not even
> +	 * initialized. This is fine, and means we can just skip the quirk
> +	 * entirely.
> +	 */
> +	if (pci_enable_device_mem(pdev)) {
> +		pci_dbg(pdev, "Can't enable device mem, no reset needed\n");
> +		return;
> +	}
> +
> +	/* Taken from drivers/gpu/drm/nouveau/engine/device/base.c */
> +	map = ioremap(pci_resource_start(pdev, 0), 0x102000);
> +	if (!map) {
> +		pci_err(pdev, "Can't map MMIO space, this is probably very bad\n");
> +		goto out_disable;
> +	}
> +
> +	/*
> +	 * Be extra careful, and make sure that the GPU firmware is posted
> +	 * before trying a reset
> +	 */
> +	if (ioread32(map + 0x2240c) & 0x2) {
> +		pci_info(pdev,
> +			 FW_BUG "GPU left initialized by EFI, resetting\n");
> +		ret = pci_reset_function(pdev);
> +		if (ret < 0)
> +			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
> +	}
> +
> +	iounmap(map);
> +out_disable:
> +	pci_disable_device(pdev);
> +}
> +
> +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1,
> +			      PCI_CLASS_DISPLAY_VGA, 8,
> +			      quirk_lenovo_thinkpad_p50_nvgpu_survives_reboot);
> -- 
> 2.20.1
>