Bug 507610 - REGRESSION: Brightness control sometimes randomly doesn't actually update brightness - and when it does, has huge delay
Summary: REGRESSION: Brightness control sometimes randomly doesn't actually update bri...
Status: RESOLVED DOWNSTREAM
Alias: None
Product: plasmashell
Classification: Plasma
Component: Brightness and Color widget (other bugs)
Version First Reported In: 6.3.6
Platform: Manjaro Linux
: NOR major
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-07-28 19:33 UTC by php4fan
Modified: 2025-07-28 20:33 UTC (History)
1 user (show)

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Description php4fan 2025-07-28 19:33:52 UTC
SUMMARY


STEPS TO REPRODUCE
1.  Click on the screen brightness tray icon
2.  adjust the brightness with the slider
3. 

EXPECTED RESULT

The brightness should change immediately in real time according to the position of the slider, every time you move it

OBSERVED RESULT

Every time you move the slider, regardless of whether it's by dragging it quickly or slowly from a value to another, or by clicking on a precise value, one of two things happens, COMPLETELY RANDOMLY:
A) the actual screen brightness changes to the new value after a couple of seconds
B) the actual screen brightness never changes, it remains at the previous value (or if you dragged the slider slowly, possibly at some random value among the ones that you passed through while moving the slider)

This renders the brightness control utterly unusable:
1) If you know perfectly the exact value of brightness that you want (and you are able to click at the exact precise position in the slider), this is "only" extremely annoying: you click on the value of brightness you want; it randomly works or not; if it doesn't, you click on some other value and then back on the value you want, and after a couple of retries if you're lucky, a few if you are not, you'll get it to work
2) If you are a normal person and want to just drag the slider slowly until you reach the brightness that you like (while obviously seeing the brightness change accordingly in real time), then you simply can't, and the brightness control is just unusable.

This is an absolutely disastrous regression.

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 6.3.6
KDE Frameworks Version: 6.16.0
Qt Version: 6.9.1
Kernel Version: 6.6.99-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 12 × 12th Gen Intel® Core™ i7-1255U
Memory: 15.3 GiB of RAM
Graphics Processor: Intel® Iris® Xe Graphics
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: Vivobook_ASUSLaptop X1502ZA_F1502ZA
System Version: 1.0

ADDITIONAL INFORMATION
Comment 1 Bug Janitor Service 2025-07-28 20:33:41 UTC
Thank you for the bug report!

However Plasma 6.3.6 no longer receives updates or maintenance from KDE; active versions are 6.4 or newer. Please upgrade to an active version as soon as your distribution makes it available to you. Plasma is a fast-moving project, and bugs in one version are often fixed in the next one.

If you need help with Plasma 6.3.6, please contact your distribution, who bears the responsibility of providing help for older releases that are no longer receiving updates from KDE.

If you can reproduce the issue after upgrading to an active version, feel free to re-open this bug report.