Created attachment 133154 [details]
dmesg after `modprobe amdgpu` and getting blackscreen

I don't know if this is specific to R9M370X - mac edition but I couldn't
reproduce it on other AMD PC I have.

This is fairly simple to reproduce, I just have to mount the amdgpu and I get a
black screen on my main screen and my main screen only (my second screen is
fine)

I don't have this problem using radeon with the exact same kernel config.
dmesg is saying everything is fine and X11 log is irrelevant because it happen
_before_ startx.
I am using Linux 4.12.4-gentoo.