Created attachment 144168 [details]
dmesg utility output

Starting X on AMDGPU takes up to a minute (about 40s, I think).
I have two video adapters, integrated NVIDIA and external R7 240.

It's only the first X startup after the boot that takes that long (and it's
exactly Xorg executable which produces the delay). All subsequent X startups
are 'normal' (fast).
So I'd expect some system configuration option gets finally set after the 1st X
startup, so maybe I could set it manually beforehand?

However, there are those dumps from AMDGPU in the dmesg log.
Didn't find anything useful on the net or in this BZ.