I edited the xconf file, and added this line to device section:

Enable brightness control=1

Now I am able to adjust brightness, but after every restart the brightness setting change back to 100%.

Is there any solution for this?


6 Answers 6


To adjust brightness in xubuntu or ubuntu Open a terminal window, and execute this command to edit /etc/rc.local:

sudo nano /etc/rc.local

Add this before the last line “exit 0″:

echo xx > /sys/class/backlight/acpi_video0/brightness

Where number xx is the value of your screen brightness of your choice.

The maximum value for brightness can be found with:

cat /sys/class/backlight/acpi_video0/max_brightness
  • for others newbie(like me): use ctrl+insert to paste the text from clipboard in nano
    – Arash
    Aug 8, 2014 at 15:14
  • How do you save it afterwards and exit?
    – Valentin
    Aug 9, 2014 at 17:47
  • 1
    Laptop with Intel card, path is: $ cat /sys/class/backlight/intel_backlight/brightness
    – Daniel
    Jun 13, 2015 at 17:44

Fix brightness control issue with Intel card in Ubuntu:(check which card is there:settings/details/graphics)

Open a terminal and create the following configuration file, if it does not exist:

touch /usr/share/X11/xorg.conf.d/20-intel.conf

Now we need to edit this file. You can use any editor be it a terminal one or graphical.

sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf

Add the following lines to this file:

Section "Device"
        Identifier  "card0"
        Driver      "intel"
        Option      "Backlight"  "intel_backlight"
        BusID       "PCI:0:2:0"


Save it. Log out and log in back. The brightness control should be working through function keys now:

  • 1
    This made my display driver to crash on 14.04 Jul 23, 2014 at 21:53
  • Mine too! this does not work and I wasn't able to get my ubuntu up and running after a reboot. Had to re-install. Sep 4, 2014 at 5:59
  • Worked for me with Ubuntu 15.04.
    – Indika K
    Jul 28, 2015 at 9:56

create a file in /usr/share/X11/xorg.conf.d/80-backlight.conf and include following in the file.

Section "Device"
    Identifier "Intel Graphics"
    Driver "intel"
    Option "AccelMethod" "sna"
    Option "Backlight" "intel_backlight" # use your backlight that works here
    BusID "PCI:0:2:0"

In /etc/default/grub make sure you have acpi_backlight=vendor in GRUB_CMDLINE_LINUX_DEFAULT.

Here is mine:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Then run update-grub and reboot.

Fixed it for me, HP ProBook w/ Intel Grpahics card, fresh 14.04 Desktop install.

  • Thx mate. I tried what not. works like charm. Do not forget to reboot Nov 2, 2015 at 5:49

Type this command in Terminal:

xrandr --output LVDS-0 --brightness 0.5

0.5 is used to decreased to adjust screen Brighness.

Should work Perfectly.

if not

xrandr --output LVDS1 --brightness 0.5

will do the job


If you want to change the screen brightness in Ubuntu

(I can’t change it using the keyboard shortcuts or the Ubuntu Power Management menu),

open a terminal and execute the following:

sudo setpci -s 00:02.0 F4.B=xx

Where xx is the desired brightness in hex ranging from 0 (brightest) to FF (no brightness at all). I usually change it to E0 when working on battery.

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