usb-display-switch

This is a script to enable or disable display standby when a USB device is added or removed.

If you have multiple computers and a USB switch device (a hub with multiple inputs and a button to toggle between them), you can use this script to also switch your display inputs automatically. When you press its button, the switch device is removed from one system and added to another. If the removed system turns the display off, and the added system turns the display on, the display will switch to the active input.

This solution is inspired by Haim Gelfenbeyn's display-switch software and article, which rely on DDC/CI to change display inputs. This didn't work for me because my display doesn't accept DDC/CI requests from inactive inputs. Instead, this script uses DPMS to control display standby, and relies on the display to automatically switch to the only input that is not on standby.

Requirements

You'll need two X11-based Linux systems, with input peripherals connected to a USB switch device, and video outputs connected to different inputs on your displays.

On each of these systems, you'll need Python 3 and pyudev. On Debian derivatives, you can install the python3-pyudev package:

sudo apt install python3-pyudev

Setup

1. Modify the usb-display-switch script to contain the vendor ID and product ID of your switch device.

   For example, when I plug in my switch device, I get the following message in dmesg:

   usb 3-9: New USB device found, idVendor=0bda, idProduct=5411, bcdDevice= 1.44
   

   So I configure the script like this:

   VENDOR_ID = 0x0BDA
   PRODUCT_ID = 0x5411
   

2. On each system you want to switch between, ensure that usb-display-switch is always running.

   To do this using the provided systemd service:

   cp usb-display-switch ~/.local/bin/
   cp usb-display-switch.service ~/.config/systemd/user/
   systemctl --user enable --now usb-display-switch