[Unit]
Description=Create the Cam Link 4K virtual camera
After=systemd-modules-load.service

[Service]
# Reruns on every relay start, so a deleted or unloaded device comes back.
Type=oneshot
ExecStart=/usr/bin/modprobe v4l2loopback
ExecStart=/bin/sh -c 'grep -qsx "Cam Link 4K" /sys/devices/virtual/video4linux/*/name || exec v4l2loopback-ctl add -n "Cam Link 4K" -x 1'