Broken rendering with PRIME on a Polaris GPU
I have a laptop with an integrated Vega 8 and a discrete RX560. For obvious reasons I would like to run games with DRI_PRIME=1. This, however, breaks gamescope (even with R600_DEBUG=nodcc, same happens with OpenGL):

Gamescope runs fine with the envvar unset, though. My system is running sway 1.7 on Arch, mesa 22.1.2 and linux-xanmod 5.18.6.
Could this be related to DRM Format Modifiers? I think I once read something like "we've merged this, but GFX8 support will be added later, so your gamescope is broken for now", but I couldn't find any info on the matter.
I'm having the same issue with my desktop (Vega 11 + RX570). Tested the same command and it spawned a gamescope window with vkcube, but couldn't get even a window to show up when trying to use the dGPU