Bug 450126

Summary:	Backlight at full brightness, uncontrollable when waking from sleep
Product:	[Plasma] Powerdevil	Reporter:	Sam <thenerdiestguy>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	kde, nate, thenerdiestguy
Priority:	NOR
Version:	5.24.0
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Sam 2022-02-13 06:28:16 UTC

SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***


STEPS TO REPRODUCE
1. Use sleep mode
2. Wake up laptop

OBSERVED RESULT
Backlight cannot be controlled until reboot, stuck at full.

EXPECTED RESULT
Backlight functions as normal

SOFTWARE/OS VERSIONS
Windows: No
macOS: No
Linux/KDE Plasma: Yes
(available in About System)
KDE Plasma Version: 5.24.0
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Lenovo Ideapad, Intel iGPU and CPU

Probably regression in 5.24.0, didn't occur in 5.23...3 was it? I don't actually remember, switched to another DE in the middle sorry
I'm using Wayland, haven't tested on X.

Comment 1 Sam 2022-02-13 11:44:57 UTC

Also, this isn't consistent. Most of the time, the backlight regains full functionality after waking up from sleep.

Comment 2 Sam 2022-02-14 17:07:29 UTC

Ok I figured out what causes this. When I plug my charger in when it's in sleep, it does this. If I unplug my charger it goes back to normal. It's also kind of inconsistent in this behavior. I'll figure out some more and provide more details.

Comment 3 Nate Graham 2022-02-16 01:30:16 UTC


*** This bug has been marked as a duplicate of bug 423556 ***

Comment 4 Sam 2022-02-16 10:39:22 UTC

Uhhhh... What? This seems like the wrong bug...

Comment 5 Sam 2022-03-09 10:43:52 UTC

NOT A BUG, actual cause is https://wiki.archlinux.org/title/Intel_graphics#Backlight_is_not_adjustable