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[GH-ISSUE #417] With Four External Monitors - Only three working #331

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opened 2026-05-05 05:45:32 -06:00 by gitea-mirror · 6 comments

gitea-mirror commented

2026-05-05 05:45:32 -06:00

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Originally created by @CharlesCCC on GitHub (Mar 28, 2021).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/417

Checklist

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

Describe the issue
I have connected my mac with 4 external monitors (2 via Displayport + 2 via HDMI)
Regardless how I connect all those four monitor, only three out of four is able to adjust the brightness.

Expected behavior
i expect all four monitors to change brightness at the same time.

Screenshots
N/A

Additional context
Any three combination will working (2 Displayport + 1 HDMI, or 2 HDMI + 1 Displayport). but not the 4th one. It felts like the App is limited to only allow control the Max 3 monitors at the same time.

Environment Information (please complete the following information):

macOS version: 11.2.3
MonitorControl version: 2.1.0 (latest)
Monitor(s): Two AOC U2790B - 4k, Two Lenovo ThinkVision P27q-20
Mac model: iMac 27inch 2019 (with 580x GPU)
Monitor Cable(s)/Connection(s): (e.g. DisplayPort): 2 displayport, 2 HDMI (tried switch them around, made no difference)

Thank you for created this great open source app.

Originally created by @CharlesCCC on GitHub (Mar 28, 2021). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/417 **Checklist**  - [x] I have searched for existing issues - [x] I have looked through [the Monitor Troubleshooting wiki](https://github.com/MonitorControl/MonitorControl/wiki/Monitor-Troubleshooting) - [x] I have updated MonitorControl to the latest version **Describe the issue** I have connected my mac with 4 external monitors (2 via Displayport + 2 via HDMI) Regardless how I connect all those four monitor, only three out of four is able to adjust the brightness. **Expected behavior** i expect all four monitors to change brightness at the same time. **Screenshots** N/A **Additional context** Any three combination will working (2 Displayport + 1 HDMI, or 2 HDMI + 1 Displayport). but not the 4th one. It felts like the App is limited to only allow control the Max 3 monitors at the same time. **Environment Information (please complete the following information):** - macOS version: 11.2.3 - MonitorControl version: 2.1.0 (latest) - Monitor(s): Two AOC U2790B - 4k, Two Lenovo ThinkVision P27q-20 - Mac model: iMac 27inch 2019 (with 580x GPU) - Monitor Cable(s)/Connection(s): (e.g. DisplayPort): 2 displayport, 2 HDMI (tried switch them around, made no difference) Thank you for created this great open source app.

gitea-mirror

2026-05-05 05:45:32 -06:00

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gitea-mirror commented

2026-05-05 05:45:40 -06:00

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

There is no such limitation built in. The display detection logic is rewritten in 3.0.0 (hopefully it will soon be released) - I'd advice to try if it helps or not. Please give a feedback whether things improved or not! Thank you!

@waydabber commented on GitHub (Aug 20, 2021): There is no such limitation built in. The display detection logic is rewritten in 3.0.0 (hopefully it will soon be released) - I'd advice to try if it helps or not. Please give a feedback whether things improved or not! Thank you!

gitea-mirror commented

2026-05-05 05:45:44 -06:00

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@waydabber commented on GitHub (Aug 25, 2021):

Hi, there seems to be an issue on the Intel side about supporting identical displays, so this issue is probably a duplicate of that one:

#49

I'll close this issue for now but please feel free to comment if there is anything we can do or if we should reopen this issue. You can comment or test the fix if available under #49! Thank you!

@waydabber commented on GitHub (Aug 25, 2021): Hi, there seems to be an issue on the Intel side about supporting identical displays, so this issue is probably a duplicate of that one: #49 I'll close this issue for now but please feel free to comment if there is anything we can do or if we should reopen this issue. You can comment or test the fix if available under #49! Thank you!

gitea-mirror commented

2026-05-05 05:45:47 -06:00

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@CharlesCCC commented on GitHub (Aug 25, 2021):

@waydabber thank you for looking into it, after reading I think #49 is similar but not exactly the same issue.
As either 2(two identical) or 3 monitors will working fine on my case (yes, the CPU is Intel based).

@CharlesCCC commented on GitHub (Aug 25, 2021): @waydabber thank you for looking into it, after reading I think #49 is similar but not exactly the same issue. As either 2(two identical) or 3 monitors will working fine on my case (yes, the CPU is Intel based).

gitea-mirror commented

2026-05-05 05:45:49 -06:00

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@waydabber commented on GitHub (Aug 25, 2021):

if any two displays are identical in a 3 or 4 display setup, you'll encounter an issue. Are you sure you are using dissimilar displays?

(ps. I am not sure I fully understand the second sentence, sorry. :))

@waydabber commented on GitHub (Aug 25, 2021): if any two displays are identical in a 3 or 4 display setup, you'll encounter an issue. Are you sure you are using dissimilar displays? (ps. I am not sure I fully understand the second sentence, sorry. :))

gitea-mirror commented

2026-05-05 05:45:52 -06:00

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@CharlesCCC commented on GitHub (Aug 25, 2021):

if any two displays are identical in a 3 or 4 display setup, you'll encounter an issue. Are you sure you are using dissimilar displays?

(ps. I am not sure I fully understand the second sentence, sorry. :))

I apologize for the miscommunication.

Based on what you said, then my issue might related with #49

@CharlesCCC commented on GitHub (Aug 25, 2021): > if any two displays are identical in a 3 or 4 display setup, you'll encounter an issue. Are you sure you are using dissimilar displays? > > (ps. I am not sure I fully understand the second sentence, sorry. :)) I apologize for the miscommunication. Based on what you said, then my issue might related with #49

gitea-mirror commented

2026-05-05 05:45:54 -06:00

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@waydabber commented on GitHub (Aug 25, 2021):

Thank you! Hopefully we'll have a fix for #49 soon and then you can try if it helps. If not, then please let me know so we can reopen this issue!

@waydabber commented on GitHub (Aug 25, 2021): Thank you! Hopefully we'll have a fix for #49 soon and then you can try if it helps. If not, then please let me know so we can reopen this issue!