I had exactly the same problem on an Asus EeePC 1015CX after installing Lubuntu 12.10.
Originally Posted by h2z
I must say I haven't tried the solution given by Malexan, you should probably try that one first:
What worked for me was this (please don't forget to read the additional notes below):
Originally Posted by Malexan
Edit the file named "brightness" in /sys/class/backlight/psb-bl, where it said 0, just write e.g. 50. In order to modify this kind of files you need to be root, so open a terminal (Accesories -> LXTerminal)
and proceed as follows:
sudo leafpad brightness
To make this change permanent you must edit the file "rc.local" in /etc. Just like this:
sudo leafpad rc.local
Where it says:
Rewrite to (again, instead of 50 you can type any number between 0 and 100):
echo 50 > /sys/class/backlight/psb-bl/brightness
- If you don't see (or don't even have) the folder "psb-bl" or the above explained doesn't work, there is another "brightness" file in /sys/class/backlight/acpi_video0.
- Some authors suggest to comment out the "exit 0" (This would be, adding a # before it) Works likewise.