Comment 3 for bug 1780237

Ah. `radeon` and `amdgpu` are trying to load together, that may not be helping:

  george@ThinkPad-E465:~$ cat /var/log/Xorg.0.log.old | grep amdgpu
  [ 29.119] loading driver: amdgpu
  [ 29.119] (==) Matched amdgpu as autoconfigured driver 0
  [ 29.119] (II) LoadModule: "amdgpu"
  [ 29.119] (II) Loading /usr/lib/xorg/modules/drivers/amdgpu_drv.so
  [ 29.143] (II) Module amdgpu: vendor="X.Org Foundation"
   All GPUs supported by the amdgpu kernel driver
  [ 29.235] (EE) AMDGPU(G0): amdgpu_device_initialize failed
  [ 29.610] (II) UnloadModule: "amdgpu"

This is a fresh installation. I've never picked either driver, and nothing appears in Additional Drivers.