> -----Original Message----- > From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf Of > Michel D?nzer > Sent: Tuesday, August 16, 2016 2:43 PM > To: Deng, Emily <Emily.Deng at amd.com> > Cc: dri-devel at lists.freedesktop.org; amd-gfx at lists.freedesktop.org > Subject: Re: [PATCH] drm/amdgpu: For virtual_display feature, define a variable > for vblank count of cpu vsync timer. > > 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 . > [[EmilyD]] Hi Michel, I means can you detail the reasons or cases that we should communicate with drm layer when don't have the vblank counter instead of pretending a hardware vblank counter in virtual DCE case. > > -- > Earthling Michel Dänzer | http://www.amd.com > Libre software enthusiast | Mesa and X developer > _______________________________________________ > amd-gfx mailing list > amd-gfx at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
