On 16/08/16 03:28 PM, Deng, Emily wrote: >> From: Michel Dänzer [mailto:michel at daenzer.net] >> Sent: Tuesday, August 16, 2016 12:01 PM >> On 16/08/16 12:49 PM, Deng, Emily wrote: >>> Hi Michel, Thanks, I still couldn't see the issue that use a variable >>> to calculate the vblank count when vsync timer interrupt occurs. I >>> just think it only emulates the hardware behavior. And the code change >>> will only in virtual display files which won't touch drm layer. I >>> incline to not modify the code in drm layer or amdgpu other codes, >>> because it may lead to other issues . >> >> I see it basically the other way around: We are currently pretending to the >> DRM >> core code that we have a reliable hardware vblank counter and timing even in >> the virtual DCE case, when we really don't. We should stop pretending and >> instead communicate the lack of these hardware facilities in the virtual DCE >> case >> as intended, otherwise we'll probably run into issues sooner or later. >> > [[EmilyD]] Hi Michel, yes, you are right, we are pretending a hardware vblank > counter in virtual DCE case to drm > layer. But can you specific some cases that we must communicate with drm > layer that we don't have the vblank counter.
I described all the necessary steps (that I know of; there may be more) in https://lists.freedesktop.org/archives/amd-gfx/2016-August/001342.html . -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
