https://bugs.freedesktop.org/show_bug.cgi?id=107045
--- Comment #4 from Michel Dänzer michel@daenzer.net --- (In reply to taijian from comment #3)
Also, so far I was always able to at least boot up with dc=0 and have it working, but that seems to be over with 4.18 (does not get past gdm login screen without freezing...).
Can you bisect that? That might lead us to the real issue here.