Bugzilla – Bug 583567
After 30 seconds of inactivity, Xorg uses 100% cpu
Last modified: 2010-03-05 07:46:12 UTC
I upgraded to KDE 4.4.0 using the packages from: http://download.opensuse.org/repositories/KDE:/KDE4:/Factory:/Desktop/openSUSE_11.2/ Since then, I notice the following behaviour: When I use my KDE desktop, the CPU usage is very low (a few percent). When I don't use it (don't move the mouse and so on), the CPU usage stays low for exactly 30 seconds. Afterwards, "top" shows me that the Xorg process uses 100% of one of my CPUs (Thinkpad T60 with Intel Core 2 Duo). "top" tells me typically: Cpu(s): 18.0%us, 35.0%sy, ... Once I move the mouse again, CPU usage goes down to almost zero again. Doing nothing for 30 seconds again, CPU usage goes up again.
I had the same issue when started using the 4.4 branch a few months ago. This bug really makes kde 4.4 unusable. It was frying my laptop. Fortunately I figured out some temporary fix which you might want to try until the issue is fixed. Go to the "Power Management" configuration applet/KDE Control Module. It has a battery on it and is usually found somewhere in the lower right corner. Click on the wrench and then on "Edit Profiles". Disable the "Dim display when idle for more than ..." field on each profile. You may also need to say "Do Nothing" to the "When the system is idle for more than ..." field on each profile. I remember I carried some experiments with different times and found that X starts using 100% cpu at exactly half of the value of one of the two options I mentioned above. I don't remember which one now. Good luck.
dup *** This bug has been marked as a duplicate of bug 584919 ***