Bug 464754

Summary:	GUI ignores external change of kbd_backlight brightness
Product:	[Unmaintained] Powerdevil	Reporter:	Werner Sembach [TUXEDO] <wse>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	colombojrj, me, natalie_clarius, nate, nicolas.fella
Priority:	NOR
Version First Reported In:	5.26.5
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Werner Sembach [TUXEDO] 2023-01-24 17:42:14 UTC

SUMMARY
Changing keyboard backlight brightness from command line or another programm then powerdevil is not shown in the gui sliders in the kcm and the tray menu.


STEPS TO REPRODUCE
1. Change value of /sys/class/leds/*kbd_backlight* via command line

OBSERVED RESULT
The kbd_backlight sliders in the plasma gui are still on their old value

EXPECTED RESULT
The kbd_backlight sliders in the plasma gui detecht the change and adjust themselfs accordingly

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kernel 5.15/Plasma 5.26.5

Comment 1 Jose Roberto 2023-05-23 19:22:43 UTC

I can confirm. Using ThinkPad T480 the keyboard backlight slide value is kept constant, even changing from external command.

Comment 2 Werner Sembach [TUXEDO] 2023-07-01 12:39:22 UTC

So I now know more: KDE uses UPower (a DBus inteface) to determine and set brightness level and UPower does not monitor external changes to sysfs/brightness, so you need to adjustthe brightness using UPower and KDE will recognize it.