Created attachment 143137 [details]
Xorg.0.log with modeset ddx instead of amdgpu ddx

(In reply to Michel Dänzer from comment #4)
> Does it also happen with the Xorg modesetting driver instead of
> xf86-video-amdgpu, or with a Wayland compositor such as GNOME on Wayland?

Ok, I've tried both the modeset ddx (Xorg.0.log attached), as well as a Wayland
compositor (plasma-wayland), and both exhibit exactly the same behavior. I used
kernel setting `amdgpu.dc=0` in both cases. Unfortunately, I can't try it with
`amdgpu.dc=1` due to issue https://bugs.freedesktop.org/show_bug.cgi?id=109238.