[saltcured]

Is that Wayland or Xorg?

With PSR in the mix, is the system really hanging or is it just failing to update the screen somehow? I.e. can you tell the difference with logs or a remote connection or configure and use an unprompted shutdown via the power button?

[Delk]

It was on Wayland. I'm not sure if I tried with X.

I can't remember the details of it. It effectively hung in the sense that I couldn't get the system into a usable state again locally without rebooting. I'm not sure if the system responded to the power button or not, or whether there was useful log output.

I didn't bother trying with a remote connection since the hang was frequent enough that it wouldn't have been of any use as a workaround anyway. I'd guess switching to another virtual console probably didn't work because I'd probably remember it if it did.

I can try re-enabling PSR and see if the problem is still there if you're interested.

[Delk]

Looks like some of the patches discussed in that bug report work around the problem by disabling PSR-SU for the specific timing controller my display also has. Those patches are in current kernels already. So basically the problem is gone for me, even if I remove the dcdebugmask.

So, I don't really know if the system was fully hanging, or if the display was just unable to update any more, but it was likely exactly the same that happened to other people with Parade TCONs in that bug discussion.