[Intel-gfx] [PATCH 3/9] drm: Don't clear vblank timestamps when vblank interrupt is disabled

[Daniel Vetter]

On Mon, May 26, 2014 at 02:46:26PM +0300, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Clearing the timestamps causes us to send zeroed timestamps to userspace
> if they get sent out in response to the drm_vblank_off(). It's better
> to send the very latest timestamp and count instead.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Do we have a kms_flip testcase which hunts for this? I guess a vblank
event with a vblank sufficiently far into the future would be useful.
Maybe call it vblank_cancel-vs-* or so. Besides the lack of testcase the
patch is Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_irq.c | 11 -----------
>  1 file changed, 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 7b1e08c..6fa7474 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -56,14 +56,6 @@
>  #define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
>  
>  /*
> - * Clear vblank timestamp buffer for a crtc.
> - */
> -static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
> -{
> -	memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time));
> -}
> -
> -/*
>   * Disable vblank irq's on crtc, make sure that last vblank count
>   * of hardware and corresponding consistent software vblank counter
>   * are preserved, even if there are any spurious vblank irq's after
> @@ -131,9 +123,6 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc)
>  		smp_mb__after_atomic_inc();
>  	}
>  
> -	/* Invalidate all timestamps while vblank irq's are off. */
> -	clear_vblank_timestamps(dev, crtc);
> -
>  	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
>  }
>  
> -- 
> 1.8.5.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch