m1ddc: I2C communication failure

I’m running macOS 12.4 on an M1 Mini with a Dell P3222QE. I get

I2C communication failure: (iokit/?) unknown subsystem error

in response to every m1ddc command.

This is a bit beyond my pay grade - should I assume the problem is with the display?

About this issue

  • Original URL
  • State: open
  • Created 2 years ago
  • Comments: 16 (6 by maintainers)

Most upvoted comments

Maybe unrelated but in my Intel MacBook, the MonitorControl app started working after the recent update Also, ignore my previous comment, I had meant to report that MonitorControl does not work on Intel MacBook and I realised now that posted it here by mistake

Yeah, some displays just won’t support DDC. It is either the HDMI port of the Mac (which has issues with DDC) or the display. I have a Lenovo Creator Extreme, it does not support DDC over the USB-C connection (even though it uses DisplayPort alt-mode) but supports it over DisplayPort for example. It is totally display firmware specific.