Created attachment 140390 [details]
First bad commit, as per git bisect

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... Maybe someone else can figure this out. 

Note that when trying to boot this build with dc=1, then bug 105760 happens.