Happening on a regular T43 too (all Thinkpads?). A workaround for me was to do "killall gnome-power-manager", then I can use the brightness keys fine.
-- [Feisty] Thinkpad R51 LCD brightness control cycles between lowest settings only https://launchpad.net/bugs/81407 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
