As described above. I start Ubuntu and the webcam-LED indicates that the webcam is active. After first real usage, for example with cheese or skype, the webcam-LED turns off. It's the same problem with the latest kernel (uname -a gives: Linux cerveau 3.3.0-999-generic #201203300409 SMP Fri Mar 30 08:10:21 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux). I've already posted a bugreport on Launchpad: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/900340