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

On 27.05.2014 23:49, Christian König wrote:

From: Christian König christian.koenig@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.