So, I just decided to get a KVM because switching inputs was annoying for my work at home setup. The issue I'm running into though is that the macbook doesn't identify my 2 external displays correctly on connect. It requires a reboot for them to identify correctly.

When they are identified incorrectly, they come up as "ITE-FHD" instead of the "LG 4k HDR" identifier they normally show. The resolution is terrible and the colors are completely off.

Anyone have any advice? I'm mostly a Windows/Linux user, and use the macbook for work as required.

Edit to add: rebooting the macbook fixes the issue, but this happens anytime it wakes from sleep, which is often when I step away from the desk for a bit.

  • The usual first fix for this is to force the screens to wake first - by pressing any button if they have one - it's usually that they're not ready when the Mac is.
    – Tetsujin
    Nov 17, 2021 at 14:36
  • 1
    You seem to be correct here. Shame that it doesn't handle the same way as my PC ruining CentOS and Windows. Oh well. Thanks for the help Nov 18, 2021 at 15:08

1 Answer 1


The issues are caused by the KVM switch does not provide full-time EDID emulation/feeding to all connected systems (both your Linux system and MacBook).

So, each time you want to make a switch to different connected systems or if the monitor connections are under power saving time-out, you will need to re-boot or replug cables to make re-initial the video bus communications between your shared monitor and connected systems.

It's a very command problem with most of the KVM switches not supporting EDID feeding functions.

Find a DDM-class KVM switch will solve the issues.

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