For searchability, here's a few of the lines I think are most useful.  Again,
the full dmesg section is attached to the original report.

[163437.787090] [drm] DM_MST: stopping TM on aconnector: 00000000286ba738 [id:
57]
[163437.787579] [drm] DM_MST: Disabling connector: 00000000032767bf [id: 64]
[master: 00000000286ba738]
[163437.787655] [drm] DM_MST: Disabling connector: 00000000fac2e679 [id: 73]
[master: 00000000286ba738]
[163437.789965] WARNING: CPU: 23 PID: 9069 at
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:2957
dm_crtc_helper_atomic_check+0x48/0x60 [amdgpu]
...
[163437.790086] RIP: 0010:dm_crtc_helper_atomic_check+0x48/0x60 [amdgpu]
...
[163437.790125] Call Trace:
[163437.790136]  drm_atomic_helper_check_planes+0x130/0x1b0 [drm_kms_helper]
...
[163438.595567] [drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us *
3000 tries - dce110_stream_encoder_dp_blank line:927
...