thinkpad-led

This little tool allows you to manage the red back led of your Thinkpad.

Build

To build the tool, just type the following command:

go build thinkpad-led.go

Optionally, you can put it under /usr/local/bin to be available under your PATH.

Usage

Usage: # thinkpad-led c̲o̲m̲m̲a̲n̲d̲
Available commands:
on → to enable the led
off → to disable the led
blink → to make it blink
help → show this page
version → show the version

Persistence

To make this tool available at boot (without setup it each time), you can automatically load the kernel module using the following commands.

What you have to do is to create 2 files to allow the kernel to load the correct module, with right parameters.

Step 1

Create the entry that will be loaded by systemd-modules-load.service.

cat << EOF > /etc/modules-load.d/ec_sys.conf
ec_sys
EOF

Step 2

Add module options under the /etc/modprobe.d directory.

cat << EOF > /etc/modprobe.d/ec_sys.conf
options ec_sys write_support=1
EOF

Step 3

Reboot the system.

reboot

Use without sudo password

(Do at your own risk)

To avoid to input the sudo password each time, you can set a specific capability. Of course, you have to make it more secure, to avoid some kind of exploitation.

First of all, you have to change the binary ownership to root.

sudo chown root:root thinkpad-led

Then, you have to reduce access to other users, giving the binary non-write permission.

sudo chmod 511 thinkpad-led

Finally, you have to set capability to enable access to kernel file.

sudo setcap CAP_DAC_OVERRIDE=ep thinkpad-led

Now, you can use thinkpad-led without input the sudo password.

Credits

I really need to thank vali20 for his amazing post on reddit: https://www.reddit.com/r/thinkpad/comments/7n8eyu/thinkpad_led_control_under_gnulinux/.

alegrey91 / thinkpad-led