[HOWTO] Laptop Screen Backlight Function Keys Don’t Dim or Brighten the Screen

If the keyboard backlight keys fail to work, here’s a solution. Append acpi_backlight=vendor to grub’s bootloader strings and to the grub’s default file so new kernel’s will also have the correct parameter.

Switch up to root

su -
Password: xxxxx

Exit the grub boot file and default file

vi /boot/grub2/grub.cfg /etc/default/grub

Search for ‘quiet’


Append ‘acpi_backlight=vendor’

A acpi_backlight=vendor

Tap Esc key

For each remaining
Tap n key to search for the next ‘quiet’ entry
Tap . to append acpi string

Tap Esc key
Save changes and move to the default file


Search for ‘quiet’


Append ‘acpi_backlight=vendor’


Tap Esc key
Save changes


Push the change to grub.cfg

grub2-mkconfig -o /boot/grub2/grub.cfg


Fedora 15, 16, 17, 18, 19

David Gregory Medina

Post created by: David Gregory Medina

Leave a Reply