Enable the keyboard backlights on supported Lenovo (e.g. Carbon X1) with command

Some Lenovo laptops have keyboard backlights, and they can be turned on using Fn + Space. There are three states: off, normal and bright.

When I start Ubuntu, these laptops always default back to a burning sun screen brightness and the keyboard lights off.

I want a medium brightness and keyboard lights on by default, because I usually use this laptop in dark environments.

The backlight is easy. Internet is filled with information about this.
echo 10 > /sys/class/backlight/acpi_video0/brightness

But how do I turn on the keyboard backlights with a command? I've been looking here but it seems to do nothing:
/sys/class/leds/tpacpi\:\:thinklight

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Updates

I tried for i in {1..32}; do xset led $i; done but nothing changes. Perhaps the keyboard backlight for Lenovo laptops has a proprietary driver and can only be controlled through tpacpi?

Also tried for i in $(find /sys/devices/platform/thinkpad_acpi/leds/ | grep /brightness\); do echo 255 > $i; done of no avail.

3

5 Answers

This is really needed to be fixed!

I think this is a common bug in new thinkpads. If you light keyboard manually fn + space then executed:

echo 0 > /sys/class/leds/tpacpi\:\:thinklight/brightness

keyboard will fade out. Please see the following link if it helps:

2

Looks as this has been updated, my X1C with ubuntuMATE 16.04 LTS has

/sys/class/leds/tpacpi\:\:kbd_backlight/brightness

which works as expected ie:

# echo 2 > /sys/class/leds/tpacpi\:\:kbd_backlight/brightness

Brings it to full light :)

2

This is the bash script I use:

Works on IBM ThinkPad X260 with Ubuntu 16.04.

3

Ok, it works fine with me with this gist:

• First of all download the gist above, I renamed it to ThinkLight.c instead of tmp.c.

• Make sure you have glib-2.0 installed:

  sudo apt-get install libglib2.0-dev

• Compile ThinkLight.c as the following:

  gcc -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include ThinkLight.c -o ThinkLight -lglib-2.0

• Load ec_sys module ( this can be added to /etc/modules on boot ):

  sudo modprobe ec_sys

• Finally execute ThinkLight with level argument (0, 1, or 2):

   sudo ./ThinkLight 0 sudo ./ThinkLight 1 sudo ./ThinkLight 2

Special thanks to hadess for making this happen!

3

My T450s would not re-enable keyboard backlight upon resume with kernels older then 4.6. FWIW, with 4.6 now, keyboard backlight is set to the brightness it had before suspend.

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