Bug 501510 - 100% brightness in the Brightness and Colour plasmoid correlates to 30% brightness in the VCP firmware, and this cannot be overridden
Summary: 100% brightness in the Brightness and Colour plasmoid correlates to 30% brigh...
Status: RESOLVED DUPLICATE of bug 500041
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (show other bugs)
Version: 6.3.2
Platform: Fedora RPMs Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL: https://discuss.kde.org/t/disable-kde...
Keywords:
: 501354 (view as bug list)
Depends on:
Blocks:
 
Reported: 2025-03-14 22:33 UTC by Roke Julian Lockhart Beedell
Modified: 2025-03-27 19:56 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
A Screenshot of the Plasmoid (23.67 KB, image/png)
2025-03-14 22:33 UTC, Roke Julian Lockhart Beedell
Details

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Description Roke Julian Lockhart Beedell 2025-03-14 22:33:26 UTC
Created attachment 179401 [details]
A Screenshot of the Plasmoid

SUMMARY

Ater invoking "ddcutil getvcp 10", I see, verbatim, the undermentioned YAML:

> VCP code 0x10 (Brightness                    ): current value =    30, max value =   100

However, as the attached screenshot depicts, the Brightness and Colour plasmoid returns 100% for this value. Consequently, I am restricted to 30% brightness, but *can* reduce it to 0%.

STEPS TO REPRODUCE

I don't know, because I don't know when this commenced. However, this OS installation is barely 4 days old, and I've done little more to it than add RPMFusion, and Mesa Freeworld from it. This did not reproduce on my previous installation, which had both modifications applied.

OBSERVED RESULT

100% in the plasmoid correlates to 30% brightness in the VCP firmware, and how to rectify this isn't evident. Attempting to modify the brightness to > 30% via "ddcutil setvcp 10 $int" momentarily applies that value before it is reverted. The same occurs if set via the monitor's integrated VCP GUI (accessible via physical buttons).

EXPECTED RESULT

100% in the plasmoid shouldn't correlate to 30% brightness in the VCP firmware. It should correlate to 100%.

SOFTWARE/OS VERSIONS

KInfo returns the undermentioned YAML:

> Operating System: Fedora Linux 41  
> KDE Plasma Version: 6.3.2  
> KDE Frameworks Version: 6.11.0  
> Qt Version: 6.8.2  
> Kernel Version: 6.13.5-200.fc41.x86_64 (64-bit)  
> Graphics Platform: Wayland  
> Graphics Processor 1: AMD Radeon RX 5700  
> Graphics Processor 2: AMD Radeon Graphics  

ADDITIONAL INFORMATION

DDCUtil's "detect" command returns the undermentioned YAML:

> Display 1  
>    I2C bus:  /dev/i2c-8  
>    DRM connector:           card1-DP-1  
>    EDID synopsis:  
>       Mfg id:               AOC - UNK  
>       Model:                Q3279WG5B  
>       Product code:         12921  (0x3279)  
>       Serial number:        
>       Binary serial number: 40899 (0x00009fc3)  
>       Manufacture year:     2019,  Week: 51  
>    VCP version:         2.2  

Additionally, this replaces https://bugs.kde.org/show_bug.cgi?id=501354#c4.
Comment 1 Roke Julian Lockhart Beedell 2025-03-14 22:33:41 UTC
*** Bug 501354 has been marked as a duplicate of this bug. ***
Comment 2 John Kizer 2025-03-27 18:50:29 UTC
Merging in with the existing bug report for this issue. Thanks!

*** This bug has been marked as a duplicate of bug 500041 ***
Comment 3 Roke Julian Lockhart Beedell 2025-03-27 19:56:48 UTC
(In reply to John Kizer from comment #2)  
Thank you!