Bug#587014: screen brightness can't be modified on some Panasonic laptops

["Axel G. Rossberg" <Axel@Rossberg.net>]

A solution for this problem that works for me (ubuntu 10.10,
2.6.35-24 kernel) is described here
http://ubuntuforums.org/showthread.php?t=1612560 

In a nutshell, add the boot option "acpi_osi=" to grub, by executing 

$ gksudo gedit /etc/default/grub

(which calls an editor) to replace in the file /etc/default/grub the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

with 

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

Then execute 

$ sudo update-grub

and reboot.  Backlight-changing should now work seamlessly.

Axel