Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

Ok well I have tried close to every single post about this problem that I could find and can not find a perm a fix for it.

The fn + brightness up/down buttons do not work at all they show it changing the brightness but it is still as max brightness and it starts to burn your eyes after a while.

What can I do to fix the problem?

I'm using the full desktop version of ubuntu.

share|improve this question

1 Answer 1

In terminal:

sudo gedit /etc/default/grub

Look for the line that says this:


Modify it as to say

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Save the file, shut down the window and insert the following in the terminal:

sudo update-grub

Reboot your laptop and (hopefully) it will work. I'm not guaranteeing anything, but this worked for my Acer and seems to work for a lot of models.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.