I built xf86-video-amdgpu package with the effective revert of the commit a2b32e72fdaf, which was mentioned in https://gitlab.freedesktop.org/drm/amd/issues/695 The test package is found in OBS home:tiwai:branches:X11:XOrg/xf86-video-amdgpu repo. Could you give it a quick try? It doesn't mean the proper solution. But if this works, it implies that you're hitting the very same as the above.