[Intel-gfx] [PATCH] i915: add page flipping ioctl

[Jesse Barnes]

On Thursday 19 February 2009 06:55:28 Chris Wilson wrote:
> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> index 3795dbc..93e677a 100644
> --- a/drivers/gpu/drm/drm_irq.c
> +++ b/drivers/gpu/drm/drm_irq.c
> @@ -435,6 +435,8 @@ EXPORT_SYMBOL(drm_vblank_get);
>   */
>  void drm_vblank_put(struct drm_device *dev, int crtc)
>  {
> +	BUG_ON (atomic_read (&dev->vblank_refcount[crtc]) == 0);
> +
>  	/* Last user schedules interrupt disable */
>  	if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
>  		mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
> @@ -460,8 +462,9 @@ void drm_vblank_pre_modeset(struct drm_device *dev,
> int crtc)
>  	 * so that interrupts remain enabled in the interim.
>  	 */
>  	if (!dev->vblank_inmodeset[crtc]) {
> -		dev->vblank_inmodeset[crtc] = 1;
> -		drm_vblank_get(dev, crtc);
> +		dev->vblank_inmodeset[crtc] = 0x1;
> +		if (drm_vblank_get(dev, crtc) == 0)
> +			dev->vblank_inmodeset[crtc] |= 0x2;
>  	}
>  }
>  EXPORT_SYMBOL(drm_vblank_pre_modeset);
> @@ -473,9 +476,12 @@ void drm_vblank_post_modeset(struct drm_device
> *dev, int crtc)
>  	if (dev->vblank_inmodeset[crtc]) {
>  		spin_lock_irqsave(&dev->vbl_lock, irqflags);
>  		dev->vblank_disable_allowed = 1;
> -		dev->vblank_inmodeset[crtc] = 0;
>  		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
> -		drm_vblank_put(dev, crtc);
> +
> +		if (dev->vblank_inmodeset[crtc] & 0x2)
> +			drm_vblank_put(dev, crtc);
> +
> +		dev->vblank_inmodeset[crtc] = 0;
>  	}
>  }
>  EXPORT_SYMBOL(drm_vblank_post_modeset);

Looks fine to me; checking for errors when calling functions is probably a 
good idea!

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center