xbacklight not working in ubuntu 16.10

Bug #1638136 reported by alim on 2016-10-31
This bug affects 24 people
Affects Status Importance Assigned to Milestone
xbacklight (Ubuntu)

Bug Description

After upgrading from 16.04 to 16.10 xbacklight is not working.
There happens nothing after executing inc or dec commands.

Running on:
- Thinkpad X240
- Ubuntu 16.10

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in xbacklight (Ubuntu):
status: New → Confirmed
alim (alimpam) wrote :

is there a workaround ? Because actually i cant set the brightness of my Notebook in i3-wm.

James Neill (jmsnll) wrote :

Also looking for a workaround if anyone has any suggestions?

lachmoewe (omg-lachmoewe) wrote :

As a workaround you could write a different value in /sys/class/backlight/intel_backlight/brightness. Requires root.

Dmitriy Geels (dmig) wrote :

xbacklight output: No outputs have backlight property

Dmitriy Geels (dmig) wrote :

Some sort of workaround:

1) add udev rule /etc/udev/rules.d/90-backlight.rules:
ACTION=="add", SUBSYSTEM=="backlight", RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness"
ACTION=="add", SUBSYSTEM=="backlight", RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"

2) add yourself to group video: sudo usermod -a -G video $USER

3) run: sudo udevadm control -R && sudo udevadm trigger -c add -s backlight

I am using this script as a workaround for my keyboard buttons: https://github.com/Skraelingjar/bright but it's not perfect.

I also came across https://github.com/snobb/xbright

It is still not working for me in 17.04

zarej (zarej-svrljig) wrote :

You can use xfce4-power-manager it is working for me, plus you can have additional benefits like notification on battery low and few more things.

$ sudo apt install xfce4-power-manager

You can add automatically start on boot at ~/.config/i3/conf
exec xfce4-power-manager

Rohith Saradhy (rohithsaradhy) wrote :

Just use light instead...
Otherwise it is a mess to fix it, especially if you have intel and nvidia graphics together!

Brinstar (brinstar) wrote :

Experiencing this issue on a Dell Vostro 3300 with Ubuntu 16.04.3 (I know the OP has reported it on 16.10)

Kalle Raiskila (kraiskil) wrote :

xbacklight stopped working just now after an 'apt updgrade'. Ubuntu 16.04.3, Dell XPS-13.
Writing directly to /sys/class/backlight/intel_backlight/brightness still works.

Kalle Raiskila (kraiskil) wrote :

In my case this turned out to be a known bug with the "modesetting" graphics driver, a fix for which would be available in linux 4.11 earliest:
Perhaps xbacklight works out-of-the-box on Ubuntu 17.10 :)

Googling around suggests Ubuntu 16.04 switched to modesetting driver recently (but I could not find definitive info on this).

Switching back to the intel driver fixed the issue for me: I edited the file
to load the "intel" driver instead of "modesetting" driver.

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