Hotkey-driven KVM: switching between Mac and Linux without leaving the keyboard

Alex Plescan rigs up a single-monitor, single-peripheral workflow for a MacBook and a Linux desktop using two ingredients: an MSI MPG 321URX monitor whose built-in KVM routes its USB hub to whichever input is active, and Display Data Channel (DDC) commands sent over the video cable to flip inputs on demand. The laptop connects via USB-C, the desktop via DisplayPort, and the monitor’s USB ports follow the active source automatically.

On macOS, m1ddc issues DDC commands to switch inputs, with Hammerspoon binding the call to Ctrl+Shift+=. On Linux under KDE, ddcutil handles the same job — feature 0x60 controls input selection, and KDE’s shortcut manager binds the command. A quirk worth noting: the USB-C port reports as a second DisplayPort because it runs in DisplayPort Alt Mode. Windows users can likely achieve the same via MSI’s bundled control software.

The payoff is a hardware-KVM-free setup where one keypress on either machine swaps the display and peripherals over without unplugging cables, touching the monitor’s buttons, or relying on a dedicated KVM switch.