My laptop brightness doesnot be darker with function key

Question

My laptop has intel hd graphics 4400, and it doesn't work well on ubuntu 14.04 , so I upgraded to ubuntu 15.04.

It works fine, but i cannot change my brightness.

The funny thing is that i can change the brightness by terminal command or at the system setting.

The max brightness value is 937, so i can edit the brightness to 300, 500 or other values by terminal command. Also I can change it brighter by function key.

But I cannot make it darker by function key!

Does anybody know how to fix this?

possible duplicate of Brightness wont change – Pilot6 May 26 '15 at 14:14 — Pilot6, May 26 '15 at 14:14
And what is your laptop model? – Pilot6 May 26 '15 at 14:25 — Pilot6, May 26 '15 at 14:25

score 0 · Answer 1 · edited Apr 13 '17 at 12:24

0

Try this:

Open a terminal
Run pkexec gedit /etc/default/grub
Type your password and the text editor will open. Find the line containing GRUB_CMDLINE_LINUX=""
Change it to GRUB_CMDLINE_LINUX="acpi_backlight=vendor".
Save the file and close the text editor.
In the terminal, now type sudo update-grub.
Reboot, and see if it works.

Source: Brightness function keys not working and Ubuntu 12.04 Wifi/Brightness Fn Keys don't work and http://thehtd.blogspot.co.uk/2012/08/brightness-problem-in-ubuntu-1204.html

By the way, it would be helpful if you could specify what laptop you're using.

edited Apr 13 '17 at 12:24

Community

1

answered May 26 '15 at 14:15

David Bailey

517

This is not needed if brightness can be controlled. – Pilot6 May 26 '15 at 14:17
@Pilot6 what do you mean? – David Bailey May 26 '15 at 14:18
I mean that editing grub config is not needed in this case. – Pilot6 May 26 '15 at 14:19
I've seen this answer in multiple locations, and it seemed to work for most people. Have you tried it? – David Bailey May 26 '15 at 14:20
Yes, this answer works in many cases, but this is not that case. – Pilot6 May 26 '15 at 14:23
I've already tried that, but it didn't work – Ki Hyun Lee May 26 '15 at 21:16

My laptop brightness doesnot be darker with function key

1 Answers1