DDC features & capabilities doesn't work with LG 32UN880-B, but works fine with another display, same model.

[pyinto]

Background

BetterDisplay: Version 3.4.1 Build 38167
MacOS: 15.3.2 (24D81)

I Have two displays, same model:

• LG 32UN880-B (1)

  • MODEL NO: 32UN880
  • PRODUCT_CODE: 32UN880- BA. AEUDMSN
  • POWER: 19.5V - 8.0A
  • MANUFACTURED: 11/2021
  • PCB Assembly Number or Mainboard/Power Board Part Number (not sure exactly what this code about): MEZ68427105(REV03)
  • EDID Report (base64): AP///////wAebVB3dbkDAAsfAQS1Rih4+nuhrk9EqSYMUFQhCADRwGFAAQEBAQEBAQEBAQEBTdAAoPBwPoAwIDUAuYghAAAaAAAA/QAoPB6HPAAKICAgICAgAAAA/ABMRyBIRFIgNEsKICAgAAAA/wAxMTFOVEtGNzYwODUKASQCAx9yIwkHB4MBAABEAQMEEOIAauMFwADmBgUBWVlSBHQAMPJwWoCwWIoAuYghAAAeVl4AoKCgKVAwIDUAuYghAAAaGjaAoHA4H0AqJjUAuYghAAAaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA6g==

• LG 32UN880-B (2)

  • MODEL NO: 32UN880
  • PRODUCT_CODE: 32UN880 - BT. AEUDMKN
  • POWER: 19.5V - 8.0A
  • MANUFACTURED: 04/2022
  • PCB Assembly Number or Mainboard/Power Board Part Number (not sure exactly what this code about): MEZ68427105(REV03)
  • EDID Report (base64): AP///////wAebVB3PRAJAAQgAQS1Rih4+nuhrk9EqSYMUFQhCADRwGFAAQEBAQEBAQEBAQEBANIAoPBwUIAwIDUAuYghAAAaAAAA/QAoPB6HPAAKICAgICAgAAAA/ABMRyBIRFIgNEsKICAgAAAA/wAyMDROVFpOSEY5ODEKAf4CAx9yIwkHB4MBAABEAQMEEOIAauMFwADmBgUBWVlSo2YAoPBwH4AwIDUAuYghAAAaVl4AoKCgKVAwIDUAuYghAAAaAjqAGHE4LUBYLEUAuYghAAAaAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAgA==

Both Displays connected to Mac Studio (ports next to each other), via usb-c to usb-c cable shipped with it.

As you can see, the only differences are manufacture date & last part of product code: AEUDMSN vs AEUDMKN (which should't be a big deal i suppose, just different region).

The Issue

When I run detect DDC features & capabilities, Display 1 works fine, and BetterDisplay detects all the features:

However, Display 2 doesn't, sometimes it even can't establish DDC communication:

Though, if I run it multiple times, the best I could get is this:

Why exactly BetterDisplay can't work with 2 same displays in the same way DDC-wise? Is there a fix it it?

What I tried

• Disconnected Display 1, and ran DDC report only with Display 2 connected
• Fully reset the BetterDisplay settings
• Reset both displays settings to initial ones
• Installed LG's OnScreen Controll app for macOS, which upgraded firmware on both displays
• Changed ports on my mac studio
• Tweaked DDC send configs:

No luck, the DDC report still performs in the same way as showed above.

[waydabber]

Hi there - I am not sure what's wrong, DDC support varies among displays, although LGs usually work well. If you try connecting only the problem display in place of the working one, do you experience the same?

[pyinto]

Hi there - I am not sure what's wrong, DDC support varies among displays, although LGs usually work well. If you try connecting only the problem display in place of the working one, do you experience the same?

yes, same issue, I also tried to disable all the peripherals on the problematic display - no effect.

[pyinto]

Hi there - I am not sure what's wrong, DDC support varies among displays, although LGs usually work well. If you try connecting only the problem display in place of the working one, do you experience the same?

Is there anything else I need to provide for better understanding of the issue?

[waydabber]

Do you have this issue with all the other DDC control apps out there? If so, it might simply be a somewhat sensitive (faulty) unit. You can also try with a different cable or switch to HDMI if using USB-C or the other way around, as these two use a completely different mechanism to relay DDC commands.

[pyinto]

@waydabber actually now I checked and even BetterDisplay DDC controls works for that display if I activate them manually and ignore that report. Except maybe {Any Color} Black Level Settings, which messes up display settings and everything turns very dark-y, and won't go back to initial values, so I have to reset it (but it's the same for non problematic display as well).
So the only issue is that report as far as I see 🙃

[waydabber]

Oh ok. Some displays indeed report no capabilities while they actually implement them. MonitorControl for example does not bother with capabilities and even BD by default does not configure them, however strongly suggests the user running the auto-configuration and then check the results. You can override the configuration anytime by changing the settings under DDC Features... :)