Version: 2.6 (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu18.1 dapper) Compiler: Target: i486-linux-gnu OS: Linux (i686) release 2.6.15-26-686 I have seen this a couple of times now. It seems to be related with a Logitech V20 USB speaker system. The KMix dialog is showing the Current mixer is "Logitech USB Speaker". 'top' shows KMix taking 97% of the CPU. But the speakers aren't plugged in. No sound is being played.
It might be enough that the card is "registered" by your Operating System. So it probably doesn't matter whethere the speakers are actually plugged in. I am pretty sure that this problem is actually "the same" as bug 127294. *** This bug has been marked as a duplicate of 127294 ***