monitor-hotplug.py

#!/usr/bin/python2

from pyudev import Context, Monitor, MonitorObserver
import subprocess
import re
import shlex


OUTPUTS = {
    'LVDS1': '--mode 1600x900 --pos 0x0 --rotate normal',
    'VGA1': '--mode 1920x1080 --pos 1600x0 --rotate normal'
}


def start_observer():
    context = Context()
    monitor = Monitor.from_netlink(context)
    monitor.filter_by(subsystem='drm')
    observer = MonitorObserver(monitor, callback=on_event, name='monitor-observer')
    observer.daemon = False
    observer.start()


def on_event(device):
    if device.action == 'change':
        run_xrandr()


def run_xrandr():
    xrandr = subprocess.check_output('xrandr').decode('UTF-8')
    command = 'xrandr'

    for output in OUTPUTS:
        connected = re.search(output + ' connected', xrandr) is not None
        if connected:
            command += ' --output %s %s' % (output, OUTPUTS[output])
        else:
            command += ' --output %s --off' % output

    subprocess.call(shlex.split(command))


if __name__ == '__main__':
    # Run xrandr based on currently connected monitors
    run_xrandr()

    # Then start listening for udev updates
    start_observer()