[GH-ISSUE #1373] MBP M1 Pro and dual LG Ultrafine 5K: "Use hardware DDC control" randomly enables itself. #782

New issue

Closed

opened 2026-05-05 06:41:50 -06:00 by gitea-mirror · 1 comment

gitea-mirror commented

2026-05-05 06:41:50 -06:00

Owner

Originally created by @julioromano on GitHub (May 15, 2023).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/1373

Before opening the issue, have you...?

Searched for existing issues
Looked through the wiki
Updated MonitorControl to the latest version (if applicable)

Describe the bug

Every now and them, completely at random, after waking the system from sleep or after disconnecting and reconnecting a display's thunderbolt cable I see that the "Use hardware DDC control" option on one of the 2 external displays is set to enabled even though I've never enabled it (it can be randomly either one of them when waking from sleep, otherwise if connecting and reconnecting one it happens on the one that has just been reconnected).
When this happens the MonitorControl menu shows the volume slider for that monitor and the brightness adjustment becomes "different" because when set to 0 it completely blacks out the display (which normally doesn't happen because this display's 0 brightness setting keeps the backlight at a very low level).

To fix this I have to go to the "Displays" tab and click "Reset settings" on the affected display. "Use hardware DDC control" will then go back to off, the volume slider disappears from the menu and the brightness adjustment goes back to normal.

It happens randomly on average 3 times per day during a full working day.

Steps to reproduce

No steps to reproduce, unfortunately. I don't do anything particular when this bug happens.

Expected behavior

"Use hardware DDC control" setting should not change by itself.

Anything else?

No response

Environment Information (please complete the following information)

- macOS version: Macos 13.3.1 (a)
- Mac model: 2021 MacbookPro 16" M1 Pro 32GB 1TB
- MonitorControl version: 4.1.0 build 7034
- Monitor(s): dual LG Ultrafine 5k (first revision, without brightness sensor)
- Apple Silicon/M1 (yes or no): yes

Originally created by @julioromano on GitHub (May 15, 2023). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/1373 ### Before opening the issue, have you...? - [X] Searched for existing issues - [X] Looked through [the wiki](https://github.com/MonitorControl/MonitorControl/wiki) - [X] Updated MonitorControl to the latest version (if applicable) ### Describe the bug Every now and them, completely at random, after waking the system from sleep or after disconnecting and reconnecting a display's thunderbolt cable I see that the "Use hardware DDC control" option on one of the 2 external displays is set to enabled even though I've never enabled it (it can be randomly either one of them when waking from sleep, otherwise if connecting and reconnecting one it happens on the one that has just been reconnected). When this happens the MonitorControl menu shows the volume slider for that monitor and the brightness adjustment becomes "different" because when set to 0 it completely blacks out the display (which normally doesn't happen because this display's 0 brightness setting keeps the backlight at a very low level). To fix this I have to go to the "Displays" tab and click "Reset settings" on the affected display. "Use hardware DDC control" will then go back to off, the volume slider disappears from the menu and the brightness adjustment goes back to normal. It happens randomly on average 3 times per day during a full working day. ### Steps to reproduce No steps to reproduce, unfortunately. I don't do anything particular when this bug happens. ### Expected behavior "Use hardware DDC control" setting should not change by itself. ### Anything else? _No response_ ### Environment Information (please complete the following information) ```markdown - macOS version: Macos 13.3.1 (a) - Mac model: 2021 MacbookPro 16" M1 Pro 32GB 1TB - MonitorControl version: 4.1.0 build 7034 - Monitor(s): dual LG Ultrafine 5k (first revision, without brightness sensor) - Apple Silicon/M1 (yes or no): yes ```

gitea-mirror closed this issue

2026-05-05 06:41:52 -06:00

gitea-mirror commented

2026-05-05 06:41:55 -06:00

Author

Owner

@waydabber commented on GitHub (May 31, 2023):

This might happen if the display's identifiers are changed. You can try BetterDisplay instead of MC and see if you have this issue. If so, then check the UUID value under the app's Settings/Displays/Show display information and see if it is different than usual or not.

@waydabber commented on GitHub (May 31, 2023): This might happen if the display's identifiers are changed. You can try [BetterDisplay](https://betterdisplay.pro) instead of MC and see if you have this issue. If so, then check the UUID value under the app's Settings/Displays/Show display information and see if it is different than usual or not. <img width="942" alt="Screenshot 2023-05-31 at 16 41 30" src="https://github.com/MonitorControl/MonitorControl/assets/37590873/d4f8ebba-6ce9-4b1f-ba4b-7545f87010d5">