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The brightness shortcuts via fn key don't work.

I tried each solution from this answer and its comments. After editing /etc/default/grub file I rebooted.

GRUB_CMDLINE_LINUX="acpi_osi=linux acpi_backlight=vendor"

What other workarounds/solutions are there?

Relevant output:

$ sudo lshw -C display
  *-display UNCLAIMED     
       description: 3D controller
       product: GK107M [GeForce GT 750M]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: latency=0
       resources: memory:f6000000-f6ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:e000(size=128) memory:f7000000-f707ffff
       description: VGA compatible controller
       product: 4th Gen Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 06
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:50 memory:f7400000-f77fffff memory:d0000000-dfffffff ioport:f000(size=64)
share|improve this question
Which GPU do You have? – Kai May 25 '14 at 14:14
@Kai I added relevant info in the question. – Ionică Bizău May 25 '14 at 14:46
Now when you say the brightness keys don't work, do you see a bar moving indicating that you are changing the brightness or does pressing the FN keys do nothing at all? – John Scott May 25 '14 at 14:53
Here's couple of my workarounds. Hope you may find it useful – Serg Apr 1 '15 at 13:51
up vote 18 down vote accepted

In the terminal:

  1. sudo gedit /etc/default/grub




    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

    Then, save the file.

  2. sudo update-grub

  3. Restart computer.

The function keys (Fn+F5/F6) should now be active.

I found out that the grub file got modified after an upgrade of the system and had to do it again.

share|improve this answer
Thanks a lot! This solved the issue. Finally! :) – Ionică Bizău Apr 20 '15 at 5:16
The acpi_osi= solution got the popup to display when I hit the function keys, but now the range it from full to one tick down from full (ie, still bright). But closer than the other solutions listed by the OP. – srlm May 19 '15 at 3:31
This worked for me on my ASUS Q550LF! Thank you so much! – Ryan Stull Jun 23 '15 at 2:19
This didn't work for me. I am running Ubuntu in an Asus Zenbook ux305 laptop. Is there some other option to fix my case? – Gocht Oct 10 '15 at 16:35
for asus rog gl552vw: intel_idle.max_cstate=1 acpi_osi= acpi_backlight=native on archlinux with kernel 4.3.3 – brauliobo Jan 27 at 18:59

To Reduce brightness follow this:

Open System Settings > Brightness & lock

From there control ur brightness

You can try this :

IF u want to change brightness through keys Follow this :

sudo apt-get install xbacklight xbacklight -set 50

Then open Settings>keyboard>shortcuts

Add custom shortcut keys and enter following commands there: enter image description here

xbacklight -dec 10

xbacklight -inc 10

share|improve this answer
I know how to modify the brightness (from UI and from xbacklight) . Also, I cannot map custom shortcuts on fn key. I already tried this. :-( – Ionică Bizău May 25 '14 at 15:16
Don't use the fn key use something else – Tejas Ghalsasi May 25 '14 at 15:26
ALT+F5, ALT+F6 were already set, but I want the fn key to work... – Ionică Bizău May 25 '14 at 16:30

It seems to me that you do not have the proprietary NVIDIA-Driver installed. If this is true you could try to install this driver using the pre-installed program 'Additional Drivers'. This should work in Ubuntu 14.04, but is likely to cause trouble in previous versions of Ubuntu without some additional software installed. So in case you do not use Ubuntu 14.04, please do not install the proprietary driver without further reading.

When the driver is installed and the brightness control still doesn't work you can try to run sudo nvidia-xconfig to generate a xorg.conf-file. Then you can edit this file using sudo gedit /etc/X11/xorg.conf and add the line

Option "RegistryDwords" "EnableBrightnessControl=1"

to Section "Device".

share|improve this answer
I won't install any proprietary drivers on my computer... – Ionică Bizău May 25 '14 at 19:49

Disclaimer: I struggled with this on Mint/Mate-18 with my Asus 305CA, and got it to work, I do not know if it works on Ubuntu as well, but try... I did this:

Get Fn F5/F6 working:

sudo emacs etc/default/grub

Change the following: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

sudo update-grub

reboot the system... Now the splash screen should show up.

Verify acpi commands with acpi_listen:


press Fn F5/F6. I got this:

video/brightnessdown BRTDN 00000087 00000000 K
video/brightnessup BRTUP 00000086 00000000 K

Add the event codes to acpi event:

sudo emacs /etc/acpi/events/asus-keyboard-backlight-down 

event=video/brightnessdown BRTDN 00000087

sudo emacs /etc/acpi/events/asus-keyboard-backlight-up

event=video/brightnessup BRTUP 00000086

Confirm you can change backlight by (where xx is an integer):

echo xx | sudo tee /sys/class/backlight/intel_backlight/brightness

Add the link to the script:

sudo emacs /etc/acpi/ 


I also set value to 10 instead of 1, as it was just too slow:

if [ "$1" = down ]; then

The actual display brightness does not follow the bar in the splash. When it is full up/down, you can still continue to press Fn F5/F6 to change brightness.

You'll need to restart acpid for it to take effect:

sudo service acpid restart
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