U2723QE, KVM using a keyboard shortcut to switch in Linux

I was trying to come up with an easy way to use a keyboard shortcut to switch my monitor + KVM under Linux. This is what I ended up coming up with in case it helps anyone else. Monitor settings can be queried and changed using the `ddcutil` utility. This was in the main repositories for me. After installing =

sudo apt install ddcutil

I could then query my monitor settings (you may need to change the number at the end to match your monitor) =

sudo ddcutil capabilities -d 1

Which gave me =

....
   Feature: 60 (Input Source)
      Values:
         1b: Unrecognized value
         0f: DisplayPort-1
         11: HDMI-1
....

Using those values I could switch between my work and person laptop using =

ddcutil setvcp 60 0x1b   # the last two inputs correspond to the values above

This command can be used in a simple bash script, but I decided to make a executable so I could run it without sudo. The c code =

// switch_screen.c
#include 
#include 
#include 
#include 
    
int main()
{
    setuid(0);
    system("ddcutil setvcp 60 0x1b"); // Change this for each computer
    return 0;
}

Compiling and setting the appropriate permissions (this could easy just be a Makefile) =

gcc switch_screen.c -o switch_screen
sudo chown root:root switch_screen
sudo chmod 7445 switch_screen

The resulting executable `switch_screen` can then be used by your favorite desktop shortcut manager.

Tested under Debian (Gnome) and Ubuntu (KDE) on a Dell U2723QE monitor. ddcutil should also be available for Fedora+ and there exists an experimental GUI, see the above link, if you are more comfortable starting with that.