(In reply to Brian Schott from comment #10)
> Just rebuilt mesa, libdrm, and xf86-video-amdgpu from git this evening. The
> kernel is the gentoo patched version of 5.2.6. The problem is not limited to
> XFCE's window manager. This is what it looks like in Dolphin:
> https://i.imgur.com/b8VLVP6.png

Does using "AMD_DEBUG=nodcc" Mesa environment variable help?

Could you capture an apitrace of the issue in Dolphin so I can reproduce more
easily?