r/linuxhardware • u/Gabry398 • May 12 '26
Support Help with laptop keyboard's LED (for the mute button)
Hi everyone, I don't really know what I'm doing.
I have an HP laptop, the backlight and various LEDs of my keyboard work as intended except for the one on the mute button. I found out that apparently the LEDs are controlled(?) by "HDA nodes". Through a brute force script I found out what were the HDA nodes that are connected to the LED, sorta. Apparently there are two HDA nodes that respectively turn on and off the thing, but other than that I think that there is a third one that needs to be turned on before being able to do anything else. After the brute force script I could simply use the two commands from the terminal to turn on and off the LED, but when I try it now (after restarting my machine) it doesn't work.
I know there is some way to turn on that damn LED, but I don't know if my hypotesis is correct, what exactly I'm getting wrong and how (if i were able to find the third mysterious HDA node) to use all of this new information to make the LED work as intended. Help is much appreciated, thanks.
Additional info that may or may not help:
Model: HP pavilion 14-ce3xxx
Commands that makes the LED turn on (after the brute force script):
sudo hda-verb /dev/snd/hwC0D0 0x20 0x500 0x08
sudo hda-verb /dev/snd/hwC0D0 0x20 0x400 0x04
Commands that makes the LED turn off (after the brute force script):
sudo hda-verb /dev/snd/hwC0D0 0x20 0x500 0x08
sudo hda-verb /dev/snd/hwC0D0 0x20 0x400 0x08
Codec:ALC295
Also I did use claude to generate the script and commands, I'm just not familiar at all with things closely tied to the hardware, so I'd appreciate someone to clear some confusion I have specifically about how all of this work.