https://bugs.freedesktop.org/show_bug.cgi?id=107045
--- Comment #10 from Michel Dänzer michel@daenzer.net --- (In reply to taijian from comment #9)
OK, so I did some git-bisect work in order to find where exactly booting with amdgpu.dc=0 broke. What I found is attached, although it does not make much sense to me...
Indeed, it's pretty much impossible for that change to cause the problem.
Most likely, the issue with amdgpu.dc=0 happens with some probability < 100%, so you'd have to test longer / several times before declaring a commit as good. (A commit where the problem occurs can immediately be marked as bad)