[MegaDeKay]

I have a shortcut on my Linux desktop to switch my Dell U3818DW display to its HDMI input where a second graphics card passed through to Windows is running on as a KVM guest.

  #!/bin/bash
  ddcutil setvcp 60 0x11

On my Windows guest desktop, I set up a shortcut for Dell Display manager to switch back to my Linux host and primary graphics card on my display's DisplayPort input

  "C:\Program Files (x86)\Dell\Dell Display Manager\ddm.exe" SetActiveInput DP

Trivial to set up and works great.

[l8rlump]

Thanks. I also discovered winddcutil, for those of us on Windows with Dell monitors too old to be supported by Dell Display Manager.

https://github.com/scottaxcell/winddcutil