I've just encountered a problem with my software brightness controls on a fresh install of Archlinux (using KDE as the desktop environment). I can adjust my display's brightness to my heart's content using the brightness keys on my keyboard, but none of the stuff in KDE power management works. In addition, I've also tried the xbacklight program without success. It doesn't give me any errors, it just fails to adjust the backlight at all. Any ideas why this is happening and what I might be able to do to fix it?
This maybe should have gone in Laptop Issues, now that I think about it.