On 04.08.2016 19:12, Daniel Stone wrote: > On 4 August 2016 at 11:01, Michel Dänzer <michel@xxxxxxxxxxx> wrote: >> On 04.08.2016 18:51, Daniel Stone wrote: >>> On 4 August 2016 at 04:39, Michel Dänzer <michel@xxxxxxxxxxx> wrote: >>>> Patch 6 extends the ioctl with new flags, which allow userspace to >>>> explicitly specify the target vblank seqno. This can also avoid delaying >>>> flips in some cases where we are already in the target vertical blank >>>> period when the ioctl is called. >>> >>> Is there open userspace for this? >> >> Sure, referenced in patch 6: >> >> https://cgit.freedesktop.org/~daenzer/xf86-video-ati/commit/?id=fc884a8af25345c32bd4104c864ecfeb9bb3db9b >> >> https://cgit.freedesktop.org/~daenzer/xf86-video-amdgpu/commit/?id=b8631a9ba49c0d0ebe5dcd1dbfb68fcfe907296f [...] >> The only change compared to the existing ioctl is that userspace can ask >> for a flip to take effect in the current vblank seqno. The code added by >> the patch checks for target vblank seqno > current vblank seqno + 1 and >> returns -EINVAL in that case. This is also documented in drm_mode.h. > > Is there any particular benefit to having split absolute/relative > modes in this case? Personally I'm struggling to see the use of > relative. See the userspace patches above. It allows userspace to set the target to the current/next vblank seqno without a DRM_IOCTL_WAIT_VBLANK round-trip (which could also result in the target getting delayed by one frame compared to using a relative target directly). >>> Is all this tested somewhere? >> >> Yes, I've been using it for a while on all my machines. > > I mean in a test suite. :) Not yet. Are you thinking of intel-gpu-tools, or something else? -- 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
