Suspend/resume issue for RX5600M/4800H (Dell G5 SE)

Brief summary of the problem:

Suspend resume hangs

Hardware description:

• Laptop model: Dell G5 SE 5505 with SmartShift
• CPU: AMD Ryzen 4800H
• GPU: RX5600M + Renoir
• System Memory: 16GB
• Display(s): Dell U2720Q
• Type of Diplay Connection: USB-C

System infomration:

• Distro name and Version: Linux Mint 20 (based on Ubuntu 20.04)
• Kernel version: 5.8-rc5 from mainline PPA (happens also with 5.7.8)
• AMD package version: No package

How to reproduce the issue:

The easiest way to reproduce would be by running the Fedora-Workstation-Live Rawhide on the Dell G5 SE 5505 with the amdgpu.runpm=0 kernel parameter to avoid crashing (due to another bug), and trying to suspend twice. The first suspend will fail to suspend, and the second suspend will completely hang. This happens regardless of if an external monitor is connected or not.

Attached files:

dmesgXorg.0.log Xorg.0.log.old

Also, machine lock ups a couple of time a day with the amdgpu.runpm=0 kernel parameter. Without it it's worse. Confirmed by other users as well: https://www.reddit.com/r/linuxhardware/comments/gu0ge2/dell_g5_15_se_amd_linux_compatibility_dgpu/

There doesn't seem to be an easy way to disable the dedicated GPU boot time. Ideally there would be a kernel parameter that would allow disabling the specific PCI ID. Nor is there a way to remove it, as hotplug removal is not supported.