[GH-ISSUE #267] Same Display is recognized different via Thunderbolt or Displayport #210

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opened 2026-05-05 05:25:10 -06:00 by gitea-mirror · 3 comments

gitea-mirror commented

2026-05-05 05:25:10 -06:00

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Originally created by @dieoma76 on GitHub (Jul 24, 2020).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/267

I do connect my LG5k right now via Thunderbolt to my MacMini 2020, MacOS Catalina (10.15.6) MonitorControl is 2.0 b640.
Controlling Brightness and Volume of the Device ONLY works via Displayport, but not when connecting via Thunderbolt - expectation was it will work either way.

Comparing how Monitor Control detects the Display in Thunderbolt vs Displayport shows it "thinks" its even a different vendor:

Here the Device via Thunderbolt (Volume/Brightness NOT working)

Here the Device via Displayport (Volume/Brightness working fine)

Is there a way to tweak MonitorControl to control the Monitor regardless of the Connection method?

Originally created by @dieoma76 on GitHub (Jul 24, 2020). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/267 I do connect my LG5k right now via Thunderbolt to my MacMini 2020, MacOS Catalina (10.15.6) MonitorControl is 2.0 b640. Controlling Brightness and Volume of the Device ONLY works via Displayport, but not when connecting via Thunderbolt - expectation was it will work either way. Comparing how Monitor Control detects the Display in Thunderbolt vs Displayport shows it "thinks" its even a different vendor: **Here the Device via Thunderbolt** (Volume/Brightness **NOT** working) ![MC_Thunderbolt](https://user-images.githubusercontent.com/65195997/88410021-0fccd900-cdd6-11ea-8a1b-66381e0e3e4b.png) **Here the Device via Displayport** (Volume/Brightness working fine) ![MC1_Displayport](https://user-images.githubusercontent.com/65195997/88410137-3f7be100-cdd6-11ea-9e42-07b551c5862e.png) Is there a way to tweak MonitorControl to control the Monitor regardless of the Connection method?

gitea-mirror

2026-05-05 05:25:10 -06:00

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gitea-mirror commented

2026-05-05 05:25:15 -06:00

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@JoniVR commented on GitHub (Aug 2, 2020):

There is not, it could just be that your thunderbolt cable doesn't properly support DDC. I'd suggest trying a different cable first (if you have one laying around). Maybe try with ddcctl first to isolate if it's a cable or MonitorControl issue.

@JoniVR commented on GitHub (Aug 2, 2020): There is not, it could just be that your thunderbolt cable doesn't properly support DDC. I'd suggest trying a different cable first (if you have one laying around). Maybe try with [ddcctl](https://github.com/kfix/ddcctl) first to isolate if it's a cable or MonitorControl issue.

gitea-mirror commented

2026-05-05 05:25:18 -06:00

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@dieoma76 commented on GitHub (Aug 2, 2020):

Well, it´s the Thunderbolt Cable that came with the Monitor. I don´t have an other one, but a different Mac: I tested the Monitor with the same cable on a MacBook Pro and here Monitor Control works as expected - i can change Brightness and Volume! But the situation does sound like #265 https://github.com/MonitorControl/MonitorControl/issues/265. The combination of MacMini 2018, Thunderbolt and Monitorcontrol seems to have issues... How can i help to fix it?

@dieoma76 commented on GitHub (Aug 2, 2020): Well, it´s the Thunderbolt Cable that came with the Monitor. I don´t have an other one, but a different Mac: I tested the Monitor with the same cable on a MacBook Pro and here Monitor Control works as expected - i can change Brightness and Volume! But the situation does sound like #265 [https://github.com/MonitorControl/MonitorControl/issues/265](url). The combination of MacMini 2018, Thunderbolt and Monitorcontrol seems to have issues... How can i help to fix it?

gitea-mirror commented

2026-05-05 05:25:18 -06:00

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

Closing in favour of #265, let's continue tracking there.

@JoniVR commented on GitHub (Aug 14, 2020): Closing in favour of #265, let's continue tracking there.