On 2018-12-20 6:38 p.m., Kazlauskas, Nicholas wrote: > On 12/20/18 12:09 PM, Daniel Vetter wrote: >> On Thu, Dec 20, 2018 at 6:03 PM Alex Deucher <alexdeucher@xxxxxxxxx> wrote: >>> On Thu, Dec 20, 2018 at 11:54 AM Daniel Vetter <daniel@xxxxxxxx> wrote: >>>> >>>> Not sure about the gamma thing since we had opposite bugs on i915 >>>> about gamma not being vsynced and tearing terribly. Cursor is special >>>> since it tends to be too small to notice tearing. >>> >>> Our cursor hw (and possibly gamma as well Nicholas? Harry?) is double >>> buffered, so we can update it any time for the most part and the >>> changes won't take affect until the next vupdate period. > > I haven't really investigated too much into the gamma stuttering issue, > but I think it's similar to the cursor update - a high volume of atomic > updates that ends up skipping over a vblank or two. FWIW, I don't think the use-cases described in https://bugs.freedesktop.org/108917 (Night Light / RedShift) involve a particularly high volume of gamma updates. I was able to reproduce the stuttering with ~10 gamma changes per second, but I suspect even a single one could cause a frame drop. I assume the issue is that gamma updates are done as separate atomic commits, which can delay other commits for page flips. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
