(In reply to Brian Schott from comment #21)
> As far as the issue about desktop corruption and lockup on login requiring
> the AMD_DEBUG=nodcc workaround:
> 
> b563460b494e9228cf5bb1aa4a70ac2499ad81fe is the first bad commit
> commit b563460b494e9228cf5bb1aa4a70ac2499ad81fe
> Author: Marek Olšák <marek.olsak@amd.com>
> Date:   Tue Jan 8 20:08:08 2019 -0500
> 
>     radeonsi: enable displayable DCC on Ravens
> 
>  src/amd/common/ac_gpu_info.c                      | 8 ++++++++
>  src/amd/vulkan/winsys/amdgpu/radv_amdgpu_winsys.c | 4 ++++
>  2 files changed, 12 insertions(+)

Could you test this commit
https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2016/diffs?commit_id=4829f697ab2ceb2fc2772cc1220acc4185e6013d
and let us know if it fixes this issue?