* Pretext: I'm not entirely sure if this issue is specific to the OSS modules as I'm using Ubuntu 20.10 and the "Pro" packages do not currently support it. I'm sure this is Linux specific as the problem does not occur in Windows.
* Related post on Ask Ubuntu: https://askubuntu.com/questions/1295100/screen-does-not-turn-off-and-random-freezes-with-radeon-oss-...
Using Ubuntu 20.10 [running with the Ubuntu supplied 5.8.0-32-generic kernel at the time of writing this]: when I have any display connected one of the Display Port ports on the back of my Sapphire RX 5600XT the displays will not blank [turn off] when I lock the screen. When the screen lock is activated, the screen will attempt to blank and will turn off for a moment; then will turn back on. However, occasionally when attempting to blank the system will freeze. The system will also freeze maybe half the time when waking the system up from suspend. I have also found that turning a display attached to a DP port on and off will occasionally freeze the system.
The system is completely frozen when this occurs, and there is never anything relevant recorded in /var/log/syslog.
The problem does not appear when only using the HDMI port on the card/not using any of the Display Ports on the card.
I believe this is a kernel module issue so I'll try and build a kernel of my own with the latest amdgpu OSS modules for now, but if anyone has any idea how to resolve this issue in some other way I'd love to know. Or, if there's anything someone can suggest to try and accumulate error/debug data on this issue, or if there's somewhere I should be submitting a report for the amdgpu OSS module developers, please let me know.
