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Sys Rq Key

The Print Screen/Sys Rq key is used for certain key combinations in linux.

As far as I understand they send commands directly to the kernel if compiled in and enabled.

They're able to be used as a last resort method to shutdown and restart a linux system relatively safely.

They can do many things like just kill the processes using the most RAM too which may save a system from needing to restart.

That's not possible

A problem with Sys Rq keys not working

I have used Linux for a few years now and tried a few different distros. KDE is my favourite desktop environment as it's good for customising and has a few windows similarites which I appreciate. The distro I have settled on is Kubuntu as it has the wide userbase ubuntu as the core an KDE as the desktop. I started with Kubuntu 18.04 which ran pretty much flawlessly and I don't remember a single crash. At the time my motherboard was quite new and a firmware issue was causing windows 7 to occasionally bluescreen so Linux being more stable was a nice surprise. I upgraded the firmware with a patch which came out around 2019 if I remember correctly and that solved the bluescreens.

Soon after the release of Kubuntu 20.04, I upgraded and while it has been mostly stable I have a had a recurring crach issue. The screen locks up completely with a no mouse movement and just a freeze of what was happening at the time of the crash. Any audio playing becomes a continual loop of less than a second which I'm gussing is just what's loaded in the audio memory although I don't really know how that works. The real problem is that this kind of crash seems completely undiagnosable and unrecoverable. I enabled the Sys Rq keys after reading about them when I had encountered this crash a few times. The system doesn't respond to them at all.

SysRq Key

I enabled the full set of keys and I know they are working because I have used them to restart after another lock up I had which was caused by moving a large amount of data to an external drive formatted with NTFS. If it's a problem with the graphics card (nvidia) then surely the Sys Rq keys should still shut down and restart the computer even if I don't get output to the screen but no amount of time waiting seems to yield this result. As Kubuntu 22.04 is out and LTS is nearly over I will be upgrading without figuring out this problem and hopefully a fresh install will fix it. If it occurs again I will try to get crash logs out of the kernel somehow but I was unsuccesful last time I tried and was left with no logs where multiple online guides told there should be after their series of steps. The worst part is as the title suggests, any mention of similar issues I could find are met with claims that the Sys Rq keys not functioning is impossible and I must have just not enabled them or in the even rarer case they can agree that it's possible, the logs not showing up is completely impossible.

Update

I have updated to Kubuntu 22.04 and the problem not only persists but seems to occur a bit more often. I have returned to trying to get some sort of crash log out in part 2.