Bug 435754

Summary:	Keyboard backlight does not turn back on after opening laptop lid if it was already on before closing the lid.
Product:	[Unmaintained] Powerdevil	Reporter:	Dave <fishnet37222>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED INTENTIONAL
Severity:	normal	CC:	nate
Priority:	NOR
Version First Reported In:	5.20.5
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Dave 2021-04-15 04:34:27 UTC

SUMMARY
I have a Lenovo ThinkPad P72 with Gentoo Linux installed on it.  In KDE's power management settings, I have the keyboard brightness enabled and set to the maximum for when the AC adapter is connected.  If I close the lid and then re-open it, the keyboard backlight remains off.  I also have it configured to do nothing when the lid is closed with the AC adapter connected.

STEPS TO REPRODUCE
1. Enable the keyboard backlight in the Power Management settings.
2. Close the laptop lid.
3. After a couple seconds, open the lid again.

OBSERVED RESULT
Keyboard backlight remains off.

EXPECTED RESULT
Keyboard backlight respects the Power Management configuration.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Gentoo Linux
(available in About System)
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
I can work around the issue by installing acpid and having it configured to turn the backlight back on when the lid is opened, but I don't believe I should have to.

Comment 1 Nate Graham 2021-04-15 16:50:48 UTC

Dies the keyboard brightness ramp up as you expect if you unplug the laptop and then plug it in again?

Comment 2 Dave 2021-04-16 00:38:16 UTC

I just now had time to try it, and the keyboard backlight turned back on after disconnecting and reconnecting the AC adapter.

Comment 3 Nate Graham 2021-04-16 01:57:32 UTC

Then this is actually working as expected, because the system only changes things when the power cord is plugged in or unplugged, or when the system enters or leaves low battery status. It doesn't change anything in response to lid closure or opening events.