Bug 450126 - Backlight at full brightness, uncontrollable when waking from sleep
Summary: Backlight at full brightness, uncontrollable when waking from sleep
Status: RESOLVED NOT A BUG
Alias: None
Product: Powerdevil
Classification: Plasma
Component: general (show other bugs)
Version: 5.24.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-02-13 06:28 UTC by Sam
Modified: 2022-03-09 10:43 UTC (History)
3 users (show)

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Latest Commit:
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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