Whenever my laptop goes into the lock screen automatically, I start to hear my fans blasting like crazy. I recognize the sound, it means something is using a whole CPU thread. My plasma version: kf5-plasma.i686 : 5.12.0-2.fc22 I found this issue on Launchpad: https://bugs.launchpad.net/ubuntu/+source/plasma-workspace/+bug/1435641 But it's not the same. I tried their suggested workaround and the problem does not disappear. I did not have the chance to SSH from another machine to check what process is using the CPU. Is there a way I can analyze it from my own machine? Reproducible: Always Steps to Reproduce: 1. Wait. 2. Lockscreen comes up. Actual Results: Fans start to blast. Expected Results: Fans do not start to blast.
you could try to just start kscreenlocker_greet program in testing mode to see whether that already triggers the CPU load.
if you have an nVidia, then chances are great that this is the same bug as #347772
This annoying bug was fixed in Plasma 5.22 *** This bug has been marked as a duplicate of bug 347772 ***