(In reply to Alex Deucher from comment #9)
> It's possible that there are issues with gpio-amdpt and pinctrl-amd that
> lead to general system stability issues, but it should be noted the the gpio
> stuff in amdgpu is completely unrelated to those modules.

I think you're right - I still do get these warnings in 4.18.9 even with the
modules blacklisted; just not all the time.

Interestingly I found the other warning I get from
amdgpu_dm/amdgpu_dm_mst_types.c can be provoked by running "xcmddc -lv". It
seems udevd does this during boot. See also bug 107456.