> -----Original Message----- > From: Michel Dänzer [mailto:michel at daenzer.net] > Sent: Tuesday, August 16, 2016 12:01 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 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. > > -- > Earthling Michel Dänzer | http://www.amd.com > Libre software enthusiast | Mesa and X developer
