I run Ubuntu 12.04 on my netbook (Acer Aspire One D255E) and I have the following problem with the brightness settings: If I want to adjust the brightness with the fn-key, I can only change between three brightness steps, but my netbook has nine brightness steps.

If I adjust the brightness in the system settings, it works fine and I can choose between nine steps, so I know they are there. They are just jumped, when I use the fn-keys. The funny thing: If I click the fn-key like crazy, I can get to the steps between, too. Does anybody have an idea, what the problem might be?


  • This also fixes the Brightness not being maximum at boot on Acer Aspire Happy 2.
    – user83106
    Aug 13, 2012 at 14:26

1 Answer 1


Easy fix. In the terminal:

gksudo gedit /etc/default/grub

You will find this line in the new opened window:


Change it to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Save and close the window and type this in the terminal:

sudo update-grub

Then reboot. Rejoice :)


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