This worked for me for a while.. I did a full update/upgrade last night.. FAIL.. back to where I started. The brightness bar moves but no effect.
sudo apt-add-repository ppa:voria/ppa
sudo apt-get update
sudo apt-get upgrade
sudo apt-get purge samsung-backlight-*
sudo apt-get install samsung-backlight
Using kernel 2.6.31-20-generic, the FN-UP and FN-DOWN keys adjust the brightness as expected.
Thanks very much!
Unfortunately, I also have an option, the default, for kernel 2.6.32-21-generic and using this, the brightness keys do not work and also wireless is inoperable. Is this a known problem?