Bug 429580 - Can't change screen brightness - OSD appears but brightness does not change
Summary: Can't change screen brightness - OSD appears but brightness does not change
Status: RESOLVED UPSTREAM
Alias: None
Product: plasmashell
Classification: Plasma
Component: general (show other bugs)
Version: 5.20.3
Platform: Other Linux
: NOR normal
Target Milestone: 1.0
Assignee: David Edmundson
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-11-24 08:44 UTC by elman
Modified: 2020-11-24 09:34 UTC (History)
1 user (show)

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Description elman 2020-11-24 08:44:11 UTC 
SUMMARY
When I try to change brightness via shortcut Fn+F2/F3, OSD appears, but brightness doesn't change. Only 0 % works, which turns display off.

This used to work, but I'm not sure which update broke it. I think I was trying smooth brightness change in 5.20.0 and it worked, so maybe some of the later updates.

Changing brightness via Energy Saving doesn't work either.

Also I tried lxqt-brightness. Lowering brightness worked fine, raising brightness did work, but looked like it was changing gamma rather than backlight intensity.

STEPS TO REPRODUCE
1. Start plasma
2. Use Fn+F2/F3 to change brightness

OBSERVED RESULT
Brightness does not change.

EXPECTED RESULT
Brightness should change.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro testing
KDE Plasma Version: 5.20.3
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.1
Comment 1 elman 2020-11-24 08:48:51 UTC 
I tried changing brightness in Windows 10 and it worked OK. So no hardware failure.
Comment 2 elman 2020-11-24 09:12:10 UTC 
Booting with latest Kernel 5.4 LTS solved the issue. So it seems problem lies with kernel and not Plasma.
Comment 3 Christoph Feck 2020-11-24 09:34:24 UTC 
Thanks for the update; changing status.