I'm new with Linux and I have an issue that I have being researching and have not been able to find a solution so far. I was wondering if any help can be given. I have an Asus Q500A with Win-8 and Ubuntu 12.04 64 bit and Whenever i log-in to Ubuntu, it does so with full screen brightness and keyboard back-light at full . How do i get rid of this? How can I tweak the start-up setting for screen brightness and disable keyboard back-light at start-up?

Note: I already tried this and is not working.

Add this to /etc/rc.local:

echo '2' > /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/brightness
echo '0' > /sys/devices/platform/applesmc.768/leds/smc::kbd_backlight/brightness
  • Did you get error after running above commands?? Sep 29, 2014 at 6:28
  • None at all, the computer start's up normally but the only problem is that boots with keyboard brightness and keyboard back-light again.
    – Jairo
    Sep 30, 2014 at 1:15

3 Answers 3


To turn off the keyboard backlight on boot, you need to add this to /etc/rc.local:

echo '0' > /sys/devices/platform/[a name related to your laptop ]/leds/smc::kbd_backlight/brightness

You have an Asus laptop but you input applesmc.768 so it didn't work. For my case I added to /etc/rc.local the following line:

echo '0' > /sys/devices/platform/dell-laptop/leds/dell\:\:kbd_backlight/brightness

and it worked.

  • This did not work for me on Ubuntu 16.04.3 LTS on a ThinkPad X230.
    – user11171
    Sep 8, 2018 at 21:19
  • I have a ThinkPad T450 and it worked but I added on rc.local before the line sleep 3
    – Tedi Çela
    May 19, 2019 at 12:36

3 years later I'm facing the same issue in Debian with Mate. I solved it this way:

  1. Create a shellscript file in any path:

    sensible-editor login.sh
  2. Add the following content to the file:

    sleep 3
    dbus-send --type=method_call --print-reply=literal --system --dest=org.freedesktop.UPower /org/freedesktop/UPower/KbdBacklight org.freedesktop.UPower.KbdBacklight.SetBrightness int32:0
  3. Go to the Startup Applications

    enter image description here

  4. Add a new item there that will call the full path to the file this way:

    sh /full/path/to/file/login.sh

Note in my case the sleep 3 was essential. You need the dbus-send to run after the backlight keyboard turns on and it turned on a few seconds after Mate started. So the waiting was needed but how many seconds might depend on each system.

Also note this approach is better than the /etc/rc.local one because you don't need to run anything as root and you can still change the backlight intensity after it runs. After updating /etc/rc.local it was fixed in 0.


I first did the same thing you did but it didn't work for me neither. you just need to add this to your /etc/rc.local:

echo '0' > /sys/class/backlight/acpi_video0/brightness

(that one worked for me)

If that doesn't work try with xbacklight

apt-get install xbacklight

after the install

xbacklight -set xx

where xx is a value you'll have to experiment with for your particular system.

For the keyboard I have no clue for now, because I'm still having the same problem.

  • xbacklight changes the screen backlight, not the keyboard backlight as the question asks about.
    – user11171
    Nov 22, 2018 at 13:10

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