(In reply to rmuncrief from comment #17)
> Yes, As I said in the beginning if you don't set amdgpu.dpm=1 the system
> boots but resume doesn't work. I presume it's because power management isn't
> working. All kernels before 4.19.x work great, and have no problem with
> resume so long as dpm is enabled.

dynamic power management is always enabled by default.  the only way to disable
it is to set dpm=0.  dpm=1 either does nothing or changes the implementation
used in the driver depending on the asic.  You shouldn't set dpm= unless you
are debugging something. For your asic, kernels 4.18 and older the default was
the original dpm implementation; setting dpm=1 used the newer powerplay code. 
For kernel 4.19 and newer, the default implementation switched to the newer
powerplay code and setting dpm=1 switched back to the older implementation.  So
removing dpm=1 is correct for 4.19 and newer.  Can you elaborate on the resume
issue?