I just bought Redgear Grimm backlight external keyboard to work with linux mint 18.3. The backlight didn't work initially and after some poking around I found


and I am able to turn on the backlight with the following command

echo 1 | sudo tee /sys/class/leds/input25::scrolllock/brightness

Now here's the problems

  1. Pressing Caps Lock key and Num Lock key disables the backlight which should not happen
  2. After that the backlight doesn't work even when pressing the Num Lock, Caps Lock and Scroll Lock key(which btw should be the actual key for this function.)

The keyboard is fine. Proved by testing it on a Windows laptop.

  • Guess: The kernel misinterprets the (USB) HID information from the keyboard (possibly because the HID descriptor is not following the standards), and assigns what it thinks as the scrolllock LED to the backlight. First step is to look at the complete LED assignment for this keyboard, and also the HID descriptor (there are questions on this site describing how to do this). – dirkt May 17 at 11:32
  • Thanks @dirkt. Will search about this. – lucifer May 17 at 11:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.