[RESEND] vmwgfx: use monotonic event timestamps

Submitted by Arnd Bergmann on Jan. 16, 2018, 5:18 p.m.

Details

Message ID 20180116171910.3259056-1-arnd@arndb.de
State New
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Series "vmwgfx: use monotonic event timestamps" ( rev: 2 ) in DRI devel

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Commit Message

Arnd Bergmann Jan. 16, 2018, 5:18 p.m.
DRM_VMW_EVENT_FENCE_SIGNALED (struct drm_vmw_event_fence) and
DRM_EVENT_VBLANK (struct drm_event_vblank) pass timestamps in 32-bit
seconds/microseconds format.

As of commit c61eef726a78 ("drm: add support for monotonic vblank
timestamps"), other DRM drivers use monotonic times for drm_event_vblank,
but vmwgfx still uses CLOCK_REALTIME for both events, which suffers from
the y2038/y2106 overflow as well as time jumps.

For consistency, this changes vmwgfx to use ktime_get_ts64 as well,
which solves those problems and avoids the deprecated do_gettimeofday()
function.

This should be transparent to to user space, as long as it doesn't
compare the time against the result of gettimeofday().

Link: https://patchwork.kernel.org/patch/10076599/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Originally sent on Nov 27. Sinclair Yeh said he'd pick it up
for the next pull request, but it's not in linux-next yet.

Resending the unchanged patch, please pick it up when you have time,
or feel free to ignore this email in case it's already in some tree
that just isn't part of linux-next but will be sent during the
next merge window.
---
 drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
index 6c5c75cf5e6c..9ed544f8958f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
@@ -901,11 +901,12 @@  static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
 	spin_lock_irq(&dev->event_lock);
 
 	if (likely(eaction->tv_sec != NULL)) {
-		struct timeval tv;
+		struct timespec64 ts;
 
-		do_gettimeofday(&tv);
-		*eaction->tv_sec = tv.tv_sec;
-		*eaction->tv_usec = tv.tv_usec;
+		ktime_get_ts64(&ts);
+		/* monotonic time, so no y2038 overflow */
+		*eaction->tv_sec = ts.tv_sec;
+		*eaction->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 	}
 
 	drm_send_event_locked(dev, eaction->event);

Comments

Hi, Arnd,

Sinclair's on paternal leave and I thought this patch was already in 
drm-next. My bad.
Dave, is it too late to pull this in for the next merge window?

/Thomas


On 01/16/2018 06:18 PM, Arnd Bergmann wrote:
> DRM_VMW_EVENT_FENCE_SIGNALED (struct drm_vmw_event_fence) and
> DRM_EVENT_VBLANK (struct drm_event_vblank) pass timestamps in 32-bit
> seconds/microseconds format.
>
> As of commit c61eef726a78 ("drm: add support for monotonic vblank
> timestamps"), other DRM drivers use monotonic times for drm_event_vblank,
> but vmwgfx still uses CLOCK_REALTIME for both events, which suffers from
> the y2038/y2106 overflow as well as time jumps.
>
> For consistency, this changes vmwgfx to use ktime_get_ts64 as well,
> which solves those problems and avoids the deprecated do_gettimeofday()
> function.
>
> This should be transparent to to user space, as long as it doesn't
> compare the time against the result of gettimeofday().
>
> Link: https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.kernel.org_patch_10076599_&d=DwIBAg&c=uilaK90D4TOVoH58JNXRgQ&r=wnSlgOCqfpNS4d02vP68_E9q2BNMCwfD2OZ_6dCFVQQ&m=8M6vawBo0zDsjbqhzV0xpOwAzX7Zm-uyGlIDnQ7-Gms&s=sHGuz0aoE9aLjVp5GALo8mYrN1bwOHW6mGpJIZmhwAc&e=
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> Originally sent on Nov 27. Sinclair Yeh said he'd pick it up
> for the next pull request, but it's not in linux-next yet.
>
> Resending the unchanged patch, please pick it up when you have time,
> or feel free to ignore this email in case it's already in some tree
> that just isn't part of linux-next but will be sent during the
> next merge window.
> ---
>   drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
> index 6c5c75cf5e6c..9ed544f8958f 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c
> @@ -901,11 +901,12 @@ static void vmw_event_fence_action_seq_passed(struct vmw_fence_action *action)
>   	spin_lock_irq(&dev->event_lock);
>   
>   	if (likely(eaction->tv_sec != NULL)) {
> -		struct timeval tv;
> +		struct timespec64 ts;
>   
> -		do_gettimeofday(&tv);
> -		*eaction->tv_sec = tv.tv_sec;
> -		*eaction->tv_usec = tv.tv_usec;
> +		ktime_get_ts64(&ts);
> +		/* monotonic time, so no y2038 overflow */
> +		*eaction->tv_sec = ts.tv_sec;
> +		*eaction->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
>   	}
>   
>   	drm_send_event_locked(dev, eaction->event);
On Tue, Jan 16, 2018 at 6:28 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote:
> Hi, Arnd,
>
> Sinclair's on paternal leave and I thought this patch was already in
> drm-next. My bad.

No worries.

> Dave, is it too late to pull this in for the next merge window?

The patch isn't urgent, it's fine to wait until after the merge window, I just
want to avoid having to send it once more as I make my way through
the remaining 'timeval' and 'timespec' users.

      Arnd
Hi, Woody,

On 01/16/2018 10:39 PM, Woody Suwalski wrote:
> Thomas, the same way my DRM patch has disappeared:
> Date
>
>     Tue, 19 Dec 2017 11:50:57 -0800
> From     Sinclair Yeh <>
> Subject     Re: [PATCH v.2] 4.15 vmgfx boot warning
>
>
>
>
> This looks okay to me.

Since this is a core DRM patch I think Sinclair was expecting it to be 
pulled in using the drm-misc tree. Did you get a comment from Daniel on 
this patch?

Thanks,
Thomas
On 01/17/2018 07:33 AM, Thomas Hellstrom wrote:
> Hi, Woody,
>
> On 01/16/2018 10:39 PM, Woody Suwalski wrote:
>> Thomas, the same way my DRM patch has disappeared:
>> Date
>>
>>     Tue, 19 Dec 2017 11:50:57 -0800
>> From     Sinclair Yeh <>
>> Subject     Re: [PATCH v.2] 4.15 vmgfx boot warning
>>
>>
>>
>>
>> This looks okay to me.
>
> Since this is a core DRM patch I think Sinclair was expecting it to be 
> pulled in using the drm-misc tree. Did you get a comment from Daniel 
> on this patch?
>
> Thanks,
> Thomas
>

Actually, checkpatch.pl complains about -ENOSYS, so I'm sending a pull 
request for v1 of this patch instead, to make everybody happy. I've 
rephrased the commit log somewhat. Hope that's OK.

/Thomas