Please include upstream commit e02f5c1bb2283cfcee68f2f0feddcc06150f13aa drm: disable uncached DMA optimization for ARM and arm64 into -stable trees v4.9 and later. It makes the radeon and amdgpu drivers work on ARM and arm64 systems, which are terminally broken currently, and since those are the only architectures affected by this patch, the risk of regressions is low. Thanks, Ard.
