[PATCH 1/2] drm: Shortcircuit vblank queries

[Michel Dänzer]

On 06.04.2015 00:40, Chris Wilson wrote:
> Avoid adding to the waitqueue and reprobing the current vblank if the
> caller is only querying the current vblank sequence and timestamp and
> so we would return immediately.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Michel Dänzer <michel at daenzer.net>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Cc: Dave Airlie <airlied at redhat.com>,
> Cc: Mario Kleiner <mario.kleiner.de at gmail.com>
> ---
>  drivers/gpu/drm/drm_irq.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 6f5dc18779e2..ba80b51b4b00 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -1617,14 +1617,16 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
>  		vblwait->request.sequence = seq + 1;
>  	}
>  
> -	DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
> -		  vblwait->request.sequence, crtc);
> -	vblank->last_wait = vblwait->request.sequence;
> -	DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
> -		    (((drm_vblank_count(dev, crtc) -
> -		       vblwait->request.sequence) <= (1 << 23)) ||
> -		     !vblank->enabled ||
> -		     !dev->irq_enabled));
> +	if (vblwait->request.sequence != seq) {
> +		DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
> +			  vblwait->request.sequence, crtc);
> +		vblank->last_wait = vblwait->request.sequence;

BTW, it looks like the last_wait field is unused  and could be removed.


> +		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
> +			    (((drm_vblank_count(dev, crtc) -
> +			       vblwait->request.sequence) <= (1 << 23)) ||
> +			     !vblank->enabled ||
> +			     !dev->irq_enabled));
> +	}
>  
>  	if (ret != -EINTR) {
>  		struct timeval now;
> 

Also, the two patches should have different and more specific shortlogs.


But apart from that, this patch is

Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>

and the second patch is

Acked-by: Michel Dänzer <michel.daenzer at amd.com>


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer