I am a novice in Ubuntu.
The usual brightness increase/decrease key combination using Fn key doesn't work in Ubuntu 12.04 as many pointed out.
I had found two solutions on this forum to set the screen brightness.
One was to make the usual key combination work answer is given here:
and the other is using the command
sudo setpci -s "00:02.0" F4.B=20
20 is a hexadecimal number representing brightness.
It's only the latter that worked in my case.
I observe that the original brightness setting is restored after resumption from sleep mode.
All I want is to keep my brightness setting permanent. How do I do that?