I had the same issue when upgrading from 10.2 to 11. It turned out to be a X.org change; I am using a swiss-french keyboard, and in /etc/X11/xorg.conf, I now have to use:
Option "XkbLayout" "ch"
Option "XkbVariant" "fr"
whereas in the previous version it was simply
Option "XkbLayout" "fr_CH"
So I'd suggest you look at that part of xorg.conf.
What keyboard layout are you using?