[Intel-gfx] [PATCH] drm/i915: Make wait-for-pending-flips more defensive

[Ville Syrjälä]

On Wed, Aug 20, 2014 at 01:13:34PM +0100, Chris Wilson wrote:
> Be sure to always flush a stuck pageflip even if we couldn't possibly
> expect one to be there.
> 
> References: https://bugs.freedesktop.org/show_bug.cgi?id=82612
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/intel_display.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a7582a46e82e..5898e7157c4c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3359,11 +3359,7 @@ void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
>  	struct drm_device *dev = crtc->dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	if (crtc->primary->fb == NULL)
> -		return;
> -
>  	WARN_ON(waitqueue_active(&dev_priv->pending_flip_queue));
> -
>  	if (WARN_ON(wait_event_timeout(dev_priv->pending_flip_queue,
>  				       !intel_crtc_has_pending_flip(crtc),
>  				       60*HZ) == 0)) {
> @@ -3378,9 +3374,11 @@ void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
>  		spin_unlock_irqrestore(&dev->event_lock, flags);
>  	}
>  
> -	mutex_lock(&dev->struct_mutex);
> -	intel_finish_fb(crtc->primary->fb);
> -	mutex_unlock(&dev->struct_mutex);
> +	if (crtc->primary->fb) {
> +		mutex_lock(&dev->struct_mutex);
> +		intel_finish_fb(crtc->primary->fb);
> +		mutex_unlock(&dev->struct_mutex);
> +	}
>  }
>  
>  /* Program iCLKIP clock to the desired frequency */
> -- 
> 2.1.0.rc1
> 
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-- 
Ville Syrjälä
Intel OTC