First, see that earlier article if you aren't familiar with the changes of the AMDGPU/Radeon code for the upcoming Linux 4.6 cycle. There was also this Radeon/AMDGPU fixes pull from earlier in the week while Alex Deucher has now squeezed in another pull request.
Changes with this third 4.6 pull request are DCE code clean-ups, HDP flush/invalidation fixes, GPU VM fixes, siwtching to drm_vblank[on|off], PX fixes, and other bug fixes. The bulk of these Radeon fixes are for the AMDGPU DRM driver for GCN 1.2+ GPUs while the only Radeon change is a fix for supporting DisplayPort 2.7GHz link setup for some hardware.
This pull ends up adding close to 400 lines of code and more details are available via the pull request for DRM-Next.