DDC input source does not work on USB-C port

[runbeer]

DDC input source works on HDMI port. But It doesn't work on USB-C port. While it was on USB-C, I selected other input sources from menu or shortcuts, but nothing happened.
My monitor: LG 27UL850
My mac: Mac Mini M1
OS version: 14 & 15

[waydabber]

The codes associated to inputs there are just generic ones, your display might need a different code. You can configure these under the display's DDC Input options under Settings/Displays. Using the configuration tool and looking at the details for inputSelect might help figure out which input codes work for your display - it's not standardized and some display don't report them properly.

[Maydaytyh]

Hi, how can I get the current DDC code? I also use the USB-C port and cannot convert.

[waydabber]

The possibly working codes should be in the DDC report (under the DDC Features.../Detect...) for inputSource if the display happens to report them correctly.

[runbeer]

If i find a correct code, then where i can apply it?

[waydabber]

You can configure the codes under the display's settings tap, under Hardware Control/Input Sources... You should edit the first column "Value".