Ok, after hours i solved it by my own:
Connected my other Keyboard (logitech wireless): Logitech Multimediakeys
worked, Cherry got stuck.
Disconnected cherry and connected it to another USB-Port: Cherry keys work.
Reconnected Cherry to old Port: Cherry keys work.
I guess the problem occured after
Update:
Tested the solution from http://ubuntuforums.org/showthread.php?p=8341194
not satisfying. Vol+/- keys do not cause notify-osd to do wild flickering
anymore but multiple key presses (raise/lower volume by 2 or more steps) are
not possible anymore.
Maybe the problem is not the xserver?
** Attachment added: "BootDmesg.txt"
http://launchpadlibrarian.net/35863353/BootDmesg.txt
** Attachment added: "CurrentDmesg.txt"
http://launchpadlibrarian.net/35863354/CurrentDmesg.txt
** Attachment added: "Dependencies.txt"
http://launchpadlibrarian.net/35863355/Dependencies.txt
** A
