https://bugs.freedesktop.org/show_bug.cgi?id=101029
--- Comment #11 from Craig stein12c@gmail.com --- ok I added the modprobe.blacklist=amdgpu to the kernel command line, wouldnt boot until I also added modprobe.blacklist=radeon. Anyways once I was in I did run sudo modprobe amdgpu and got the usual "AMD-Vi: Completion-Wait loop timed out" amongst other errors. It did log some strange things in kern.log and syslog. I also ran dmesg -k >/home/craig/DMESG.txt and it created a file with nothing in it. I will attach the kern.log and syslog... not sure if that helps, as you can see i am very new at doing this kind of thing.