[GH-ISSUE #252] LG HDR 5K not accepting commands via Thunderbolt but Displayport? #198

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opened 2026-05-05 05:22:55 -06:00 by gitea-mirror · 5 comments

gitea-mirror commented

2026-05-05 05:22:55 -06:00

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Originally created by @dieoma76 on GitHub (Jul 9, 2020).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/252

Setup is a MacMini 2018 i5 latest OS (10.15.5) connected to a LG 34WK95U via LG provided Thunderbolt Cable. Neither Volume nor Brightness can be adjusted via MoniktorControl (1.7.1 b574). If i connect the Monitor via Displayport i can change Volume and Brightness. Accoding to Monitor Control the Modell ID of the Monitor is 0x7721 from Vendor 0x9E6D.

Expected behavior
same functionality via Thunderbolt as well as via Displayport Connection

Screenshots

Any ideas? Any way to troubleshoot?

Originally created by @dieoma76 on GitHub (Jul 9, 2020). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/252 Setup is a MacMini 2018 i5 latest OS (10.15.5) connected to a LG 34WK95U via LG provided Thunderbolt Cable. Neither Volume nor Brightness can be adjusted via MoniktorControl (1.7.1 b574). If i connect the Monitor via Displayport i can change Volume and Brightness. Accoding to Monitor Control the Modell ID of the Monitor is 0x7721 from Vendor 0x9E6D. **Expected behavior** same functionality via Thunderbolt as well as via Displayport Connection **Screenshots** ![image](https://user-images.githubusercontent.com/65195997/87095476-176e7880-c241-11ea-9b21-48ff9a46d9ef.png) Any ideas? Any way to troubleshoot?

gitea-mirror

2026-05-05 05:22:55 -06:00

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gitea-mirror commented

2026-05-05 05:23:00 -06:00

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@daffydowden commented on GitHub (Aug 3, 2020):

I'm in the same boat. @dieoma76, did you get any further with this?

@daffydowden commented on GitHub (Aug 3, 2020): I'm in the same boat. @dieoma76, did you get any further with this?

gitea-mirror commented

2026-05-05 05:23:02 -06:00

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@JoniVR commented on GitHub (Aug 14, 2020):

Read the troubleshooting wiki as advised in the checklist (which you removed) on this issue. It's a known issue that some cables/connections don't work or support DDC, it's not a software issue most of the time, it's hardware.

@JoniVR commented on GitHub (Aug 14, 2020): Read the [troubleshooting wiki](https://github.com/MonitorControl/MonitorControl/wiki/Monitor-Troubleshooting) as advised in the checklist (which you removed) on this issue. It's a known issue that some cables/connections don't work or support DDC, it's not a software issue most of the time, it's hardware.

gitea-mirror commented

2026-05-05 05:23:04 -06:00

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@dieoma76 commented on GitHub (Aug 14, 2020):

well, it´s NOT the cable. This issue is related to this one: In essence: Connecting the same cable to a MacBook Pro MonitorControl works as expected. I assume it´s related to a Combination of integrated Intel GPU and MonitorControl...

@dieoma76 commented on GitHub (Aug 14, 2020): well, it´s NOT the cable. This issue is related to [this one](https://github.com/MonitorControl/MonitorControl/issues/267#issuecomment-667718051): In essence: Connecting the same cable to a MacBook Pro MonitorControl works as expected. I assume it´s related to a Combination of integrated Intel GPU and MonitorControl...

gitea-mirror commented

2026-05-05 05:23:05 -06:00

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@JoniVR commented on GitHub (Aug 14, 2020):

Apologies if I came off rude, it's easy to get in an automated reply state with these issues but it's no excuse.

That makes sense. I'm going to be closing that one and the other ones as there seem to be a lot of issues that basically point to the same issue with the Mac Mini. Duplicate issues will only lower the chances of finding a solution I think. So I'll try to keep the best one open and reference.

@JoniVR commented on GitHub (Aug 14, 2020): Apologies if I came off rude, it's easy to get in an automated reply state with these issues but it's no excuse. That makes sense. I'm going to be closing that one and the other ones as there seem to be a lot of issues that basically point to the same issue with the Mac Mini. Duplicate issues will only lower the chances of finding a solution I think. So I'll try to keep the best one open and reference.

gitea-mirror commented

2026-05-05 05:23:06 -06:00

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@dieoma76 commented on GitHub (Aug 15, 2020):

no Problem and fully agree: Let´s follow up on #267 - i assume many tickets can be closed if we can fix this one finally. Let me know if i can help with tests or further diagnostics...

@dieoma76 commented on GitHub (Aug 15, 2020): no Problem and fully agree: Let´s follow up on #267 - i assume many tickets can be closed if we can fix this one finally. Let me know if i can help with tests or further diagnostics...