>> Any graphic gl rendering instantly nullifies screen lock on linux.
>> on nvidia, radeon, or intel improperly, so really don't even know
>> who to bug.
>
> What are the steps to reproducing this? I found a completely different
> problem when I tried to manually lock the screen. The root window went
> black, and white text saying something like "The screen unlocker is
> broken, do (thing that doesn't work) to unlock the screen." How did
> this happen? It worked months ago....
For me, using the desktop normally, then launching any sort of gl rendered game, minecraft or secondlife that I'll leave running for days, wait the 10 minutes, and observe the screen not locking. It's not only these graphic games, but even some things like clicking on a menu on a window (ie. file), leaving it open, but not actually selecting things, tends to as well freeze and hang the lock screen process from kicking off. Anything Java like menus or modal windows too tend to freeze screen lock from engaging. Far too many things. The screen never dims, goes to lock, it's just stuck in a perpetual state of active it seems. This has happened since the beginning of time for me on about every hardware and gpu combination possible, so more than just a nvidia driver bug or something.
I agree with the rest of the comments, I can't expect much debugging with 6 displays, but would be nice if they'd listen to someone who actually did as I'm likely not the first or last to try. Now that I'm down to 3 from the 6, I think it's a bit more common a setup, only with the 4k displays and hdmi connections cause more weirdness.
The issue stems from my samsung 4k tv's (not monitors) in use, that they do not power down ala a monitor would, so I have to shut them off at night when going to bed or leaving the office with a remote. This causes them to hotplug remove from the graphics, leaving no displays attached, which causes kwin to poop on itself. Originally in 4 and early 5, this would just crash kde, and later they added a null framebuffer back in to deal with this. It still causes long-term destabilization when I do this more than a few times over days, and every time rearranges every window on my desktop to one display, presuming the first to reattach.
Cinnamon did this too, but within a day of bringing it up, a workaround was proposed and never had another issue with it, and is now fixed in new builds. if only I could say the same for kde after some combination of these and other bugs over the years.
-mb