Turn a $30 USB switch into a full-featured KVM
This utility watches for USB device connect/disconnect events and switches monitor inputs via DDC/CI. This turns a simple USB switch into a full-fledged KVM solution: press one button on your USB switch and all your monitors connect to a different input.
It is supposed to be installed on all computers that could be connected to these monitors, since the app only switches monitors "one way" and relies on itself running on the other computers to switch it "the other way" as needed.
The app is written twice: once for MacOS (in Swift) and once for Windows (in Rust). The idea is dead simple, but I haven't found good cross-platform support for DDC, USB, device plug-n-play and power management in any one language except C, and I didn't want to write this in C.
The configuration is pretty similar on both platforms:
On MacOS: the configuration file is expected in
~/Library/Preferences/display-switch.ini On Windows:
the configuration file is expected in
Configuration file settings:
usb_device = "1050:0407" monitor_input = "Hdmi1"
usb_device is which USB device to watch (vendor id
/ device id in hex), and
monitor_input is which
monitor input to switch to, when this device is connected.
Supported values are
DisplayPort2 If your
monitor has an USB-C port, it's usually reported as
On MacOS: the log file is written to the system log. On WindowS:
the log file is written to
Building from source
Install Rust, then do
--release from inside Windows directory.
Install Xcode, then do
display_switch -configuration release -derivedDataPath .build
build from inside MacOS directory.
Running on startup
target\release (where it was built in the previous
Menu\Programs\Startup (replace Username with your Windows
# Get your INI file in order! (see above) cp .build/Build/Products/Release/display_switch /usr/local/bin cp dev.haim.display-switch.daemon.plist ~/Library/LaunchAgents/ launchctl load ~/Library/LaunchAgents/dev.haim.display-switch.daemon.plist