[PATCH 5/5] drm/radeon: rework page flip handling v3

[Michel Dänzer]

On 27.05.2014 23:49, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
> 
> Instead of trying to flip inside the vblank period when
> the buffer is idle, offload blocking for idle to a kernel
> thread and program the flip directly into the hardware.
> 
> v2: add error handling, fix EBUSY handling
> v3: add proper exclusive_lock handling

[...]

> +	/* update crtc fb */
> +	crtc->primary->fb = fb;
> +
> +	/* We borrow the event spin lock for protecting flip_work */
> +	spin_lock_irqsave(&crtc->dev->event_lock, flags);
> +
> +	if (radeon_crtc->flip_work) {
> +		DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
> +		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> +		drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base);
> +		radeon_fence_unref(&work->fence);
> +		kfree(work);
> +		return -EBUSY;
> +	}

If we return -EBUSY, we shouldn't change crtc->primary->fb, should we? I
wonder if crtc->primary->fb shouldn't be changed in
radeon_flip_work_func(), when we're sure we can actually flip.


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