Problem with backlight gmux_backlight

I have a similar issue. Here is my output. Noob here so not sure what to do with this info.

ls /sys/class/backlight/

lrwxrwxrwx 0 root 26 Jan 16:50 gmux_backlight -> ../../devices/pnp0/00:03/backlight/gmux_backlight
lrwxrwxrwx 0 root 26 Jan 16:50 intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card1/card1-LVDS-2/intel_backlight

systemctl status [email protected]*

fish: No matches for wildcard “[email protected]”. See help expand.
systemctl status [email protected]

Thanks in advance for any help.

This failure is because of fish. Try this

bash -c 'systemctl status [email protected]*'

Also post your system info

inxi -Fxxxza

Have you read the explanations on the initial topic? They should help you understand the issue, or maybe it is totally different.

Use proper format for terminal output.

System info:


OK. I think it's time you describe your problem and provide journal error messages. Read this systemd/Journal - ArchWiki

1 Like

So what is happening is my screen brightness does not change whether I use the panel or keyboard controls. The pop up appears and bar changes when I increase or decrease it but that actual brightness of the screen remains constant.



You need to learn about filtering journalctl. That's why I gave you the link. Your posted part is useless for the case. For example:

journalctl -b -g backlight --no-pager --no-hostname

When posting terminal output about one or two pages, post in the forum post directly. If it's longer use bin.garuda.

Type: Laptop System: Apple product: MacBookPro9,1

Special case.
There is an Archwiki page for this. Read it, especially about Fn keys fix and backlight. It suggests an AUR package, which is now not existent.
Maybe try another one, like hbacklight, but you have to read dev's instructions.

1 Like

Ahh ok thank you. I'll try that. Thanks bearing with my noobness.