[RESEND] drm/i915: register vga switcheroo later, unregister earlier

Submitted by Jani Nikula on Oct. 6, 2019, 9:46 a.m.

Details

Message ID 20191006094643.28824-1-jani.nikula@intel.com
State New
Headers show
Series "drm/i915: register vga switcheroo later, unregister earlier" ( rev: 2 1 ) in Intel GFX

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Commit Message

Jani Nikula Oct. 6, 2019, 9:46 a.m.
Move vga switcheroo and dsm handler register later in
i915_driver_register(), and unregister in i915_driver_unregister(). The
dsm handler unregister is a nop, and is only added for completeness.

My unsubstantiated suspicion is that the vga switcheroo state change
would not work as early as we register the hooks currently. In any case
exposing the interfaces to the world only after we've got everything set
up seems prudent.

Also replace the error handling in vga switcheroo register with a simple
error message. This is done at the same time due to lack of error
propagation from i915_driver_register().

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 9354924576c4..63d47d699305 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -289,12 +289,6 @@  static int i915_driver_modeset_probe(struct drm_i915_private *i915)
 	if (ret)
 		goto out;
 
-	intel_register_dsm_handler();
-
-	ret = i915_switcheroo_register(i915);
-	if (ret)
-		goto cleanup_vga_client;
-
 	/* must happen before intel_power_domains_init_hw() on VLV/CHV */
 	intel_update_rawclk(i915);
 
@@ -343,8 +337,6 @@  static int i915_driver_modeset_probe(struct drm_i915_private *i915)
 cleanup_csr:
 	intel_csr_ucode_fini(i915);
 	intel_power_domains_driver_remove(i915);
-	i915_switcheroo_unregister(i915);
-cleanup_vga_client:
 	intel_vga_unregister(i915);
 out:
 	return ret;
@@ -356,8 +348,6 @@  static void i915_driver_modeset_remove(struct drm_i915_private *i915)
 
 	intel_bios_driver_remove(i915);
 
-	i915_switcheroo_unregister(i915);
-
 	intel_vga_unregister(i915);
 
 	intel_csr_ucode_fini(i915);
@@ -1344,6 +1334,11 @@  static void i915_driver_register(struct drm_i915_private *dev_priv)
 
 	intel_power_domains_enable(dev_priv);
 	intel_runtime_pm_enable(&dev_priv->runtime_pm);
+
+	intel_register_dsm_handler();
+
+	if (i915_switcheroo_register(dev_priv))
+		DRM_ERROR("Failed to register vga switcheroo!\n");
 }
 
 /**
@@ -1352,6 +1347,10 @@  static void i915_driver_register(struct drm_i915_private *dev_priv)
  */
 static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 {
+	i915_switcheroo_unregister(dev_priv);
+
+	intel_unregister_dsm_handler();
+
 	intel_runtime_pm_disable(&dev_priv->runtime_pm);
 	intel_power_domains_disable(dev_priv);
 

Comments

On Sun, Oct 06, 2019 at 12:46:43PM +0300, Jani Nikula wrote:
> Move vga switcheroo and dsm handler register later in
> i915_driver_register(), and unregister in i915_driver_unregister(). The
> dsm handler unregister is a nop, and is only added for completeness.
> 
> My unsubstantiated suspicion is that the vga switcheroo state change
> would not work as early as we register the hooks currently. In any case
> exposing the interfaces to the world only after we've got everything set
> up seems prudent.
> 
> Also replace the error handling in vga switcheroo register with a simple
> error message. This is done at the same time due to lack of error
> propagation from i915_driver_register().
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Acked-by: Lukas Wunner <lukas@wunner.de>

Seems like a good idea to limp on instead of bailing out if vga_switcheroo
registration fails.

Taking a brief look at intel_acpi.c, I notice intel_dsm_detect() checks
for presence of exactly 2 devices with class PCI_CLASS_DISPLAY_VGA.
This breaks if a third GPU is attached via Thunderbolt or CardBus.
Not sure if that can happen in reality, I suspect the DSM is only
present on older laptops?

I'm also confused that intel_acpi.c doesn't register a vga_switcheroo
handler.  Is the mux controlled by a separate ACPI method and the one
checked for in intel_acpi.c is only used to gather system information?

Thanks,

Lukas

> ---
>  drivers/gpu/drm/i915/i915_drv.c | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 9354924576c4..63d47d699305 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -289,12 +289,6 @@ static int i915_driver_modeset_probe(struct drm_i915_private *i915)
>  	if (ret)
>  		goto out;
>  
> -	intel_register_dsm_handler();
> -
> -	ret = i915_switcheroo_register(i915);
> -	if (ret)
> -		goto cleanup_vga_client;
> -
>  	/* must happen before intel_power_domains_init_hw() on VLV/CHV */
>  	intel_update_rawclk(i915);
>  
> @@ -343,8 +337,6 @@ static int i915_driver_modeset_probe(struct drm_i915_private *i915)
>  cleanup_csr:
>  	intel_csr_ucode_fini(i915);
>  	intel_power_domains_driver_remove(i915);
> -	i915_switcheroo_unregister(i915);
> -cleanup_vga_client:
>  	intel_vga_unregister(i915);
>  out:
>  	return ret;
> @@ -356,8 +348,6 @@ static void i915_driver_modeset_remove(struct drm_i915_private *i915)
>  
>  	intel_bios_driver_remove(i915);
>  
> -	i915_switcheroo_unregister(i915);
> -
>  	intel_vga_unregister(i915);
>  
>  	intel_csr_ucode_fini(i915);
> @@ -1344,6 +1334,11 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
>  
>  	intel_power_domains_enable(dev_priv);
>  	intel_runtime_pm_enable(&dev_priv->runtime_pm);
> +
> +	intel_register_dsm_handler();
> +
> +	if (i915_switcheroo_register(dev_priv))
> +		DRM_ERROR("Failed to register vga switcheroo!\n");
>  }
>  
>  /**
> @@ -1352,6 +1347,10 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
>   */
>  static void i915_driver_unregister(struct drm_i915_private *dev_priv)
>  {
> +	i915_switcheroo_unregister(dev_priv);
> +
> +	intel_unregister_dsm_handler();
> +
>  	intel_runtime_pm_disable(&dev_priv->runtime_pm);
>  	intel_power_domains_disable(dev_priv);
>  
> -- 
> 2.20.1
>