I merged the riastradh-drm2 branch to HEAD today. This shouldn't cause any problems for anyone, because it touched very little outside sys/external/bsd/drm2 -- it's not hooked into any kernels other than the new amd64/DRMKMS one. But let me know if you observe any fallout.
Update to userland X.org should be coming soon, so that userlands can take advantage of the new DRM/KMS drivers.