KDE unresponsible after screensaver is locked for several hours.

Hi all, I’m currently using Gentoo ~x86 on a Macbook Pro and I’d been facing a really annoying bug for sometime before I could apply a workaround to it.

The bug sympthons are a very unresponsible system after leaving the screen locked for several hours, ie. all night, for instance, simply unlocking it was almost impossible. It was also possible to see intense flickering of the screensaver unlock dialog.

Logging to the terminal was possible though and I found out that there were many kdesktop_lock instances running (more than 80) and they were eating up all machine resources. Killing all of them (ie. pkill kdesktop_lock) would bring the system back to life.

To understand what was happening I left a tiny script logging the number of kdesktop_lock instances all night so I could check the results the other day. It was then interesting to find out that two instances were being spawned every 5 minutes. Note that my screensaver timeout is 5 minutes, and I use two screens on KDE.

Probable cause, maybe due to the existance of a second monitor, KDE is failing to tell the screensaver is already active and is spawning a couple more, one for each screen, everytime the screensaver timeout is due.

Unfortunately I’m currently unable to investigate this bug in deeper detail due to our current QEdje project but, meanwhile you can avoid it by disabling automatic screensaver and starting it manually when needed.