Ubuntu 20.04 Lenovo laptop keyboard backlight

Question

I am currently running Ubuntu 20.04 on a Lenovo E595 laptop. I swapped out the physical keyboard with one that is backlit (confirmed by the presence of the "key" light label on the spacebar). The connectors do physically line-up (The only difference is that the backlit keyboard ribbon cable runs a couple extra traces in already existing plastic). The issue is that I cannot activate the backlight at all.

My question is if I can turn it on, what is the way to do so.

I did some preliminary searches:

• Enable the keyboard backlights on supported Lenovo (e.g. Carbon X1) with command
• https://www.reddit.com/r/thinkpad/comments/9actmm/keyboard_backlight_w_ubuntu_1804/

In all, the results and solutions varied as follows:

1. Run the Windows keyboard driver using Wine
2. Modify the /sys/class/leds/tpacpi::kbd_backlight/brightness file
3. Modify the /sys/class/leds/tpacpi::thinklight/brightness file
4. Modify specific bytes under characters files under /sys/.../ec/ec0 (and other locations I cannot recall)
5. Press "Fn + Space" (which is the logical thing to do)

The issues with each are:

1. Using Wine to run a driver is not optimal and not guaranteed to work.
2. On this system, this file does not appear
3. On this system, there is no entry for "tpacpi::thinklight/brightness", but there is an entry for "tpacpi::thinkvantage/brightness", but has no affect on the keyboard backlight.
4. The programs written to modify this value are seemingly specific to the device it was written for.
5. Linux is reading the Fn key as a keypress instead of allowing the firmware (if any) to use it as a modifier key. This can be seen running the showkey command. For me, it returns a value of 143. This could be leveraged, if there was another way to adjust the backlight manually.

Some additional notes:

• In addition, I have accounted for the Fn and Control key swap.
• I've toggled the different BIOS options for Fn key settings with no change.

Answer 1

Not sure if you got this issue sorted for yourself. I have been struggling to get this fixed. I finally managed it. You are right, kbd_backlight is not active by default. Reboot your machine, enter BIOS. Enable hardware acceleration under the virtualisation section. Post which the backlight should start working. If not, kbd_backlight would now be active and you can edit the values to change the backlight settings. Hope this works for you too. Cheers!

Answer 2

In some cases you will not find tpacpi::kbd_backlight That was my case, I hava a Lenovo/Thinkpad T480 20L6 which "does not have" support for keyboard backlight. However after some time I bought a keyboard with backlight support --->

However, even after installation and reboot, the backlight led did not work. But now, the problem was the BIOS. So I've entered in Lenovo support site and downloaded the BIOS Update Utility (Linux) v1.45 from 23 Aug 2022. It gave me a zip file. Once decompressed, I just ran sudo fwupdmgr install N24ET70W.cab. But still did not work flawless, I had to edit the file /etc/fwupd/daemon.conf and turn to false the key OnlyTrusted=false, then I ran the fwupdmgr command again, restarted the machine, and finally it worked!