(In reply to freedesktop from comment #27)
> OK there seems to be something screwy going on with the amdgpu.dpm option -
> if that's set to 0, it still results in a blank screen. It has to be removed
> entirely from the kernel command line for boot to work for me on 4.19.
> 
> I'm not sure if that's a different bug or not, but can anyone who had
> success with removing the option, also test with amdgpu.dpm=0 to see if it
> still results in a blank screen?
> 
> Also, are FD BZ email notifications broken for anyone else?

I'm seeing the same thing. amdgpu.dpm=0 causes a blank screen, leaving it out
enables the system to boot.