(In reply to Robert Strube from comment #30)
> Hi Alex,
> 
> Thanks for the reply.  I wanted to clarify an important point: When I
> disabled PM completely and ACPI completely, I did not see any PCI resource
> issues AND the eGPU initialized successfully.
> 
> acpi=off apm=off amdgpu.dpm=0 amdgpu.aspm=0 amdgpu.runpm=0 amdgpu.bapm=0

the only relevant items here are acpi=off and amdgpu.dpm=0.  Did you test them
independently or just together?  setting dpm=0 is irrelevant if acpi=off since
there will be no resource restrictions.  You need to test them independently.

> 
> I've been working with another user that has the exact same system (XPS
> 9575) and an RX 580 and is having the same issues.  He was actually able to
> get the eGPU initialized by passing in PCI=noacpi rather than completely
> disabling ACPI as a whole.  I'll double check with him to see if he can post
> his dmesg log - because I'm not sure if the PCI resource issues are present
> under those circumstances.

looks like the same issue as yours.  PCI resources not getting assigned.