Arch Linux

LeFauconBlanc

Member

From: USA

Registered: 2026-03-23

Posts: 16

[SOLVED] KDE Plasma Keyboard Backlight UPower Issues

Whenever I use my "adjust keyboard backlight brightness" command on my Lenovo ThinkPad (Fn + Space) it works, but in KDE Plasma I don't get any brightness popup that I usually do and the Brightness & Color applet shows NO changes (it does show changes for my "change screen brightness keys", UNTIL I restart upower.service THEN it works as normal and if I stop upower.service after starting it, then it replicates my problem exactly but the problem is is that whenever my laptop boots up it shows no error with upower.service and that it was started successfully. I've already tried enabling upower.service but to no avail. I'm not familiar with keyboard backlights in systems administration so all help is appreciated.

Video: https://imgur.com/a/FGlIwoG

Last edited by LeFauconBlanc (2026-09-29 00:55:42)

LenJacob

Member

Registered: 2026-09-27

Posts: 1

Re: [SOLVED] KDE Plasma Keyboard Backlight UPower Issues

I am also experiencing this behaviour on another distro (Fedora).  This problem is not ArchLinux specific.  Your message is the first search result which describes the problem and offers a solution.  Running: 

systemctl restart upower.service

...does fix the problem and brings back KDE's on-screen backlight indicator.  This problem is also noted on Fedora's Discussion as is your message.  I don't know if I can post full links here, but check: discussion . fedoraproject . org and look for issue # 202974.  Lastly, I cannot find a KDE bug report about this issue when searching: bugs . kde . org

LeFauconBlanc

Member

From: USA

Registered: 2026-03-23

Posts: 16

Re: [SOLVED] KDE Plasma Keyboard Backlight UPower Issues

Solution: Downgrade UPower to 1.91.3-1. Likely an upstream bug.

Last edited by LeFauconBlanc (2026-09-29 00:55:26)

Ruhanilinks

Member

Registered: 2026-09-11

Posts: 22

Re: [SOLVED] KDE Plasma Keyboard Backlight UPower Issues

Since restarting `upower.service` immediately fixes the keyboard backlight detection, it seems like Plasma itself may not be the problem. I’d check the UPower logs and the detected backlight devices during boot to see why the keyboard backlight isn’t being exposed correctly until UPower is restarted. Could be a startup ordering issue.