Bug 511872 - blue flash while changing brightness with night mode (reduced bluelight) on
Summary: blue flash while changing brightness with night mode (reduced bluelight) on
Status: RESOLVED WORKSFORME
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (other bugs)
Version First Reported In: 6.5.1
Platform: Other Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-11-09 16:31 UTC by Dietmar Czekay
Modified: 2025-12-04 16:46 UTC (History)
1 user (show)

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Version Fixed/Implemented In:
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Description Dietmar Czekay 2025-11-09 16:31:39 UTC 
SUMMARY
if red shift mode is on at night, changing the brightness with laptop key code, there is a short blueish flash on all screens. It seems to be, the blue channel is powered 100% for a twinkle of a eye and then the scren is dimmed down or up and blue is set back to the color temperature set before in settings.

STEPS TO REPRODUCE
1. enable night light mode
2. set warm white light for night
3. after activated, dim down or up with key combination

OBSERVED RESULT
blue flash and then dimming

EXPECTED RESULT
just dimming

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 6.17.7
KDE Plasma Version: 6.5.2
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2

ADDITIONAL INFORMATION
Debian Sid
Comment 1 TraceyC 2025-12-03 16:20:34 UTC 
I'm not able to reproduce this on
Plasma built from git-master on a laptop with an AMD graphics card
Plasma 6.5.3 on a laptop with an NVIDIA card, KF 6.20.0, Qt 6.10.1

What graphics card do you have? If it's NVIDIA, are you using the proprietary driver?
Comment 2 Dietmar Czekay 2025-12-03 21:39:07 UTC 
Hmmm, these are my system settings:

Betriebssystem: Debian GNU/Linux 13
KDE-Plasma-Version: 6.5.3
KDE-Frameworks-Version: 6.20.0
Qt-Version: 6.9.2
Kernel-Version: 6.17.9+deb14-amd64 (64-bit)
Grafik-Plattform: Wayland
Prozessoren: 12 × AMD Ryzen AI 5 PRO 340 w/ Radeon 840M
Speicher: 32 GiB of RAM (30,5 GiB usable)
Grafikprozessor: AMD Radeon 840M Graphics
Hersteller: Dell Inc.
Produktname: Dell Pro 16 PC16255
Comment 3 Dietmar Czekay 2025-12-03 22:01:38 UTC 
In plasma 6.5.3 it's gone.
Only thing I see, stepping down the dimming via keyboard dims first the integrated screen to 70% and then the external screens start dimming.
Comment 4 TraceyC 2025-12-04 16:46:20 UTC 
(In reply to Dietmar Czekay from comment #3)
> In plasma 6.5.3 it's gone.
> Only thing I see, stepping down the dimming via keyboard dims first the
> integrated screen to 70% and then the external screens start dimming.

Thanks for following up. It sounds like the issue that was originally reported is fixed.

With the second issue, that the external screens start dimming after the integrated screen - is that a new issue? As in, did they used to all dim at the same time before? If so, can you please open a new report about it? Thanks.