On 10/01/17 09:07 PM, Andy Furniss wrote: > Andy Furniss wrote: > >> Though recent testing shows this is not true with DAL/DC on 3.7 - >> todo test DC on new drm-next branch. > > todo done, DC for some reason on both amd-staging-4.7 and > amd-staging-drm-next is "slower" = the tear region is 2 to 3 times > larger than non DC kernel with powerplay auto. With high it is smaller > but still present.
This particular issue is because DC uses the GPU's VUPDATE interrupt instead of the VBLANK interrupt to drive the DRM vblank machinery. The result is that userspace is only notified of a vertical blank period when it's already over, so it doesn't get a chance to do anything inside the vertical blank period. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev