Since yesterday I have this problem: sometimes, after some use, the sytem (Debian Squeeze) becomes a little unresponsive to mouse and keyboard (some clicks and keystrockes are lost). It is as if a "mute" key is always pressed.
If I switch to console (ctrl-alt-F1), I see a cotinuous series of ^@^@^@. This stop and start if I press capslock.
In recent updates I can't see anything related to this.
Any ideas?