The only dmesg errors are these:

[309092.861665] [drm:radeon_cs_ioctl] *ERROR* Failed to parse relocation -12!
[309099.062192] radeon 0000:01:00.0: bo ffff8803fc4cb400 don't has a mapping in
vm ffff8803f406b580
[309099.063303] radeon 0000:01:00.0: bo ffff8803fc4cf400 don't has a mapping in
vm ffff8803f406b580
[309099.064403] radeon 0000:01:00.0: bo ffff8803fc4c9800 don't has a mapping in
vm ffff8803f406b580
[309099.065457] radeon 0000:01:00.0: bo ffff8803fc4cc800 don't has a mapping in
vm ffff8803f406b580
[309099.066560] radeon 0000:01:00.0: bo ffff8803fc4cb800 don't has a mapping in
vm ffff8803f406b580
[309099.067664] radeon 0000:01:00.0: bo ffff8803fc4c9c00 don't has a mapping in
vm ffff8803f406b580

agd5f mentioned that those are normal though. (well, not *normal* but can be
ignored)