Bug 516087 - "Control hardware brightness with DDC/CI" option is present in the KCM even when DDC/CI is off in the OSD menu of the monitor
Summary: "Control hardware brightness with DDC/CI" option is present in the KCM even w...
Status: CONFIRMED
Alias: None
Product: systemsettings
Classification: Applications
Component: kcm_kscreen (other bugs)
Version First Reported In: 6.5.91
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: kscreen-bugs-null@kde.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2026-02-16 13:00 UTC by Patrick Silva
Modified: 2026-02-16 16:44 UTC (History)
2 users (show)

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

Attachments
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2026-02-16 13:00 UTC, Patrick Silva 		Details
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Description Patrick Silva 2026-02-16 13:00:13 UTC 
Created attachment 189651 [details]
screenshot

SUMMARY
There is an option to turn DDC/CI on/off in the OSD menu of my monitor.
The "Control hardware brightness with DDC/CI" option is unexpectedly present in the KCM (and checked) even when DDC/CI is set to off in the OSD menu of my monitor. And the slider used to set the brightness is missing.

STEPS TO REPRODUCE
1. turn DDC/CI fesature off in the OSD menu of the monitor
2. open Display Configuration KCM
3. 

OBSERVED RESULT
"Control hardware brightness with DDC/CI" option is unexpectedly present in the KCM (and checked).
Please see the attached screenshot.

EXPECTED RESULT
hide "Control hardware brightness with DDC/CI" option when DDC/CI feature is off in the OSD menu of the monitor

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.5.91
KDE Frameworks Version: 6.23.0
Qt Version: 6.11.0
Graphics Platform: Wayland
Comment 1 Oliver Beard 2026-02-16 14:50:00 UTC 
Does `ddcutil detect` fail to find the monitor with DDC/CI turned off monitor-side?
Comment 2 Patrick Silva 2026-02-16 14:54:29 UTC 
$ ddcutil detect
Invalid display
   I2C bus:  /dev/i2c-4
   DRM_connector:           card0-HDMI-A-1
   EDID synopsis:
      Mfg id:               CMT - UNK
      Model:                GA25FC
      Product code:         9650  (0x25b2)
      Serial number:        xxxxxxxxxxxx
      Binary serial number: 0 (0x00000000)
      Manufacture year:     2025,  Week: 29
   This monitor does not support DDC/CI. (I2C slave address x37 is unresponsive.)
Comment 3 Oliver Beard 2026-02-16 16:44:02 UTC 
I suppose it also shouldn't appear with HDR where brightness is managed by software.

I will mark this as CONFIRMED.