I'm seeing this too, occasionally, Uwe. I don't use the sky2 driver, but I do use the nVidia driver. Hmmm.
You may find it useful to try and unlock the keyboard with Alt+SysRq+K...if this doesn't work, you can safely reboot with Alt+SysRq+R+K+S+U+B (the letters are in sequence, not simultaneously). This is much better than hard rebooting, I've been told.
-Benjamin Kudria
