Brightness function keys not working

12.10 laptop brightness function-keys

25,657

Solution 1

Try adding acpi_backlight=vendor as a boot option. To do that, open a terminal window, and run

gksu gedit /etc/default/grub

Locate this line: GRUB_CMDLINE_LINUX="".

Edit it to look like this: GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

Save the file, then, in a terminal, run sudo update-grub.

Reboot, and check if the brightness keys work.

Solution 2

You can try to control it from command line and give mesage back if this works in general:

You will need xrandr

xrandr --current --verbose - this will display your current display mode / modes

important is name of your output (clould be LVDS1 or LVDS-0)

xrandr --output <outputname> --brightness 0.5 - this should control your brightnes, you can try different values. Do not use zero (0) what means lamp is switched off and you will see Big nothing. be careful, some types of devices have completely different set of values (as 0-255, etc. Unfortunatelly I do not have your ASUS to test it)

This will work probably independently of the brightness settings reachable normally via keys. If this works, I recommend to watch for key bindings. Advantage is, you can control brightness of external VGA output as well.

25,657

Halta

Updated on September 18, 2022

Comments

Halta over 1 year

I have an ASUS X55A-SPD0204O laptop. The rest of the FN+Fx (where x = number) like sound + - mute, screen turn off, wireless etc. work perfectly.

The problem is with the 2 brightness keys. They just won't work. Any suggestions?
- Admin about 11 years
  
  Can you please add the output of ls /sys/class/backlight and of cat /sys/class/backlight/*/brightness to the question.
- Admin about 11 years
  
  I'd also be interested in seeing the output of lspci | grep -i vga, as we might be dealing with hybrid graphics.
- Admin over 7 years
  
  Why is this question closed as "has been asked before" with a reference to a question asked after this one? Not to mention that the referenced question in turn actually references this question.
unknownone about 11 years

Worked perfectly for my Asus UL50VT. Been trying to fix this problem for several years now. Thanks!
Halta about 11 years

unfortunately this didn't work
AFwcxx about 11 years

nope, doesn't work for me too. The indicator doesn't even pops up when i press those keys.
AliN about 11 years

@Dialogos, try acpi_osi=Linux or acpi_osi=linux acpi_backlight=vendor; I hope one of these will help.
Halta about 11 years

yes i can change it manually.
Halta about 11 years

there's no such file.
Stichoza over 10 years

Neither acpi_backlight=vendor nor acpi_osi=linux acpi_backlight=vendor worked for me. The working one for me was acpi_osi=Linux as @AliNa commented. Debian Wheezy on Asus UX50V Laptop
Ankush Agrawal about 10 years

Worked on Ubuntu 14.04, HP Pavilion G6. Thanks!
avalancha about 10 years

acpi_osi_Linux did it for me, too, thanks @Stichoza
umpirsky almost 10 years

@Dialogos askubuntu.com/questions/217758/how-to-make-an-xorg-conf-file
Florian Loch almost 10 years

First suggestion solved it for me on Ubuntu 14.04 running on a Lenovo ThinkPad
Andreas over 7 years

acpi_osi=Linux worked for me on 16.10, but there is no OSD when changing the brightness with the keys. Is that to be expected or can it be done?