I have a Acer Aspire 5755 with Intel video graphic, on Ubuntu 14.04, the combination Fn+/(Right/left) arrows can increase/decrease the brightness screen. Works fine on unity and with a grub modification (boot flags acpi_osi=Linux and backlight=vendor) the hot key work on any desktop environment.

I make a direct upgrade to 14.10, and the hot key can not work, even with grub modification. But i can chance the screen brightness in System settings → Brightness and Lock.

ls /sys/class/backlight/

Anyone have a solution?

  • I had the same problem on a Dell laptop that also uses intel_backlight, however for me the solution required getting rid of the boot flags. See if this answer helps. – TheSchwa Oct 27 '14 at 6:46

I make some tests removing the grub flags. It doesn't work, but when I reintroduce the flags

GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor splash"

and run sudo update-grub the hot keys start to work again. Now I can control the screen brightness with key combination.


I read a fix somewhere about that for Ubuntu 14.04.

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

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

Now you 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"EndSection

Save it. Log out and log in back

If it doesn't work simply go to usr/share/X11/xorg.conf.d and delete the 20-intel.conf file.


Since I cannot add an upvote or a comment i'll just do a repeat of Rick's answer but now in a different laptop running ubuntu 14.04. Here's the set up

  Acer Aspire V5
  Ubuntu 14.04 (updated several times)
  Linux Kernel 3.13.0-52-generic
  Intel graphics card

All i had to do was to edit the default grub file in the configuration directory /etc and then update the grub a restart and everything was okay HOT KEYS are back (serious face)!. instructions

   Fire your terminal >> **CTRL + ALT + T**
   Enter the following command >> **sudo vim /etc/default/grub**
   (or any other text editor you like)
   then find the line **GRUB_CMDLINE_LINUX_DEFAULT=""** (if it's not there then create one below GRUB_TIMEOUT=""

   put the following boot flags to enable the hot keys >> **quiet acpi_backlight=vendor splash**

   so in the end you have the following >> **GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor splash"**

I beleive that this configuration will work for most Acer Computers that are running Ubuntu. Good luck!

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