R9 390 hangs at boot with DPM/DC enabled for kernels 4.19.x and above, says KMS not supported

Submitted by rmu..@..ce.com

Assigned to Default DRI bug account

Link to original bug (#109135)

Description

Created attachment 142874
Example of failed amdgpu boot with R9 390.

I'm running the latest Manjaro and have a Sapphire Nitro R9 390. Kernels before 4.19.x work great with amdgpu, but all kernels from 4.19.x on hang at boot, and usually don't even generate a boot log, no matter how long you wait.

However after compiling and testing the latest linux-amd-wip-git I was able to get a log so I can finally file a bug. By the way, I've gotten a few logs before but lost them while debugging, however this time I had the sense to save it.

In nay case, the error line is always the same:

AMDGPU(0): [KMS] drm report modesetting isn't supported.

This only happens if you set amdgpu.dpm=1 and/or amdgpu.dc=1 with the bad kernels. If you leave those options out amdgpu works, but things like resuming from suspend, etc. don't work.

I've attached Xorg.0.good.log to show a good boot with kernel 4.18.20, and a Xorg.0.bad.log to show the failed boot with amd-wip-git. And by the way I've tried numerous kernels over the last weeks and they all fail the same way, but if you want me to test a specific kernel I'll be happy to do so.

Here's the grub line I use for all testing:
GRUB_CMDLINE_LINUX_DEFAULT="quiet resume=UUID=b4f71480-8fe3-43c2-99c9-fc3f5687545b libata.atapi_passthru16=0 rd.modules-load=vfio-pci amd_iommu=on iommu=pt amdgpu.modeset=1 radeon.si_support=0 radeon.cik_support=0 amdgpu.si_support=1 amdgpu.cik_support=1 amdgpu.dpm=1 amdgpu.dc=1"

Attachment 142874, "Example of failed amdgpu boot with R9 390.":
Xorg.0.bad.log