Bug 500799

Summary:	External monitor brightness jumps to 100% after it sleeps and wakes up, even with Plasma 6.3.2 and ddcutil 2.2.0
Product:	[Plasma] plasmashell	Reporter:	indisputable <ovi.dev>
Component:	Power management & brightness	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	aspotashev, jpetso, jurajoravec, kdedev, natalie_clarius, nate
Priority:	NOR
Version First Reported In:	master
Target Milestone:	1.0
Platform:	Kubuntu
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=506122
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description indisputable 2025-02-27 05:22:15 UTC

SUMMARY
After updating to the latest KDE version, my main monitor sets brightness to 100% after restarting. However, sometimes, when I click on the brightness widget, it only identifies one monitor. So, I have to reconnect the cable to be able to set brightness to both monitors.


STEPS TO REPRODUCE
1. Update kde to 6.3.2
2. Set monitor brightness to 20%
3. Restart 

OBSERVED RESULT
The main monitor is 100% brightness

EXPECTED RESULT
The main monitor should be at 20% brightness

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Tuxedo OS
KDE Plasma Version: 6.3.2
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION
I'm using a non-tuxedo laptop, Wayland.

Comment 1 Nate Graham 2025-02-28 17:35:03 UTC

Do you What ddcutil version do you have? If it's not 2.2.0, any chance you could find a way to upgrade to 2.2.0 (you might need to build it from source) and see if that fixes it?

I ask because there's a fix in Plasma 6.3.2 that's supposed to fix most of these issues, and ddcutil 2.2.0 is supposed to fix the rest.

Comment 2 Nate Graham 2025-02-28 17:40:19 UTC

I ask because if ddcutil 2.2.0 fixes it, this is Bug 500337 and the solution is to upgrade ddcutil. That would be something to talk to your distro about.

Comment 3 indisputable 2025-02-28 18:25:47 UTC

I have a laptop and second monitor connected via HDMI cable. I have updated ddcutil to 2.2.0. But it didn't fix it.
But the brightness goes to 100% after restart or shutdown only for the laptop monitor.
It's not a major problem, I can adjust it every time I turn on my machine...

Comment 4 Nate Graham 2025-02-28 20:26:20 UTC

Darn. Thanks for checking!

Comment 5 Bug Janitor Service 2025-03-15 03:47:33 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!

Comment 6 indisputable 2025-06-26 18:03:26 UTC

Recently, I switched to Fedora 42 from Tuxedo OS. So far, brightness for all the monitors works very well. After setting the brightness and restarting the PC, brightness levels remains the same.

Comment 7 TraceyC 2025-07-23 14:58:03 UTC

I'm glad to hear this is working properly for you now. I'll close out this report. If anything new crops up, don't hesitate to send us another report.