[GH-ISSUE #472] LG Ultrafine 5K brightness change override by system setting. #378

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opened 2026-05-05 05:51:28 -06:00 by gitea-mirror · 2 comments

gitea-mirror commented

2026-05-05 05:51:28 -06:00

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Originally created by @joechen1105 on GitHub (Jul 25, 2021).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/472

Originally assigned to: @waydabber on GitHub.

Checklist

I have searched for existing issues
I have looked through the wiki
I have updated MonitorControl to the latest version

Describe the bug
A clear and concise description of what the bug is.
Monitor control got override by system brightness setting.

To Reproduce
Steps to reproduce the behavior:
-adjust brightness through Monitor Control
-brightness changes during adjustment
-brightness changed back to original setting

Go to '...'
Click on '....'
Scroll down to '....'
See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.

Environment Information (please complete the following information):

macOS version: 11.4
Mac model: MacBook Pro 15 2018
MonitorControl version: 2.1
Monitor(s):LG Ultrafine 5K
Apple Silicon/M1 (yes or no):no

Originally created by @joechen1105 on GitHub (Jul 25, 2021). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/472 Originally assigned to: @waydabber on GitHub. **Checklist**   - [x] I have searched for existing issues - [x] I have looked through [the wiki](https://github.com/MonitorControl/MonitorControl/wiki) - [x] I have updated MonitorControl to the latest version **Describe the bug** A clear and concise description of what the bug is. Monitor control got override by system brightness setting. **To Reproduce** Steps to reproduce the behavior: -adjust brightness through Monitor Control -brightness changes during adjustment -brightness changed back to original setting 1. Go to '...' 2. Click on '....' 3. Scroll down to '....' 4. See error **Expected behavior** A clear and concise description of what you expected to happen. **Screenshots** If applicable, add screenshots to help explain your problem. **Additional context** Add any other context about the problem here. **Environment Information (please complete the following information):** - macOS version: 11.4 - Mac model: MacBook Pro 15 2018 - MonitorControl version: 2.1 - Monitor(s):LG Ultrafine 5K - Apple Silicon/M1 (yes or no):no

gitea-mirror

2026-05-05 05:51:28 -06:00

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gitea-mirror commented

2026-05-05 05:51:37 -06:00

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@waydabber commented on GitHub (Aug 20, 2021):

This problem lies in the fact that the LG Ultrafine 5K should not be controlled via DDC but via DisplayServices as this display knows Apple's USB MCCS protocol. In case of DDC control macOS is not aware of changes and will revert any change whenever it feels it needs to change brightness for whatever reason.

I plan to add this functionality in an upcoming version. The issue is tracked here:

https://github.com/MonitorControl/MonitorControl/issues/364

I will close this issue now, but please if you have anything to add let me know in that thread + also if the issue is updated, we'll need you as a tester (if you have to time) to test the update on this display. Thank you!

@waydabber commented on GitHub (Aug 20, 2021): This problem lies in the fact that the LG Ultrafine 5K should not be controlled via DDC but via DisplayServices as this display knows Apple's USB MCCS protocol. In case of DDC control macOS is not aware of changes and will revert any change whenever it feels it needs to change brightness for whatever reason. I plan to add this functionality in an upcoming version. The issue is tracked here: https://github.com/MonitorControl/MonitorControl/issues/364 I will close this issue now, but please if you have anything to add let me know in that thread + also if the issue is updated, we'll need you as a tester (if you have to time) to test the update on this display. Thank you!

gitea-mirror commented

2026-05-05 05:51:40 -06:00

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@waydabber commented on GitHub (Sep 3, 2021):

For those with Apple displays, there is a link to a test build with proper support here: https://github.com/MonitorControl/MonitorControl/issues/539

@waydabber commented on GitHub (Sep 3, 2021): For those with Apple displays, there is a link to a test build with proper support here: https://github.com/MonitorControl/MonitorControl/issues/539