Home / ubuntu / Questions / 104982
Accepted
Ken Kinder
Asked: 2012-02-17 23:46:18 +0800 CST

If I just use a window manager and not a desktop environment, how do I get automatic dock/undock resolution updates?

  • 772

Gnome and KDE both change resolutions when I dock/undock my laptop.

They seem to do it automatically, more or less, based on the state of the computer. I'd like to have that behavior if I just run something like IceWM or Openbox. Or even XFCE.

Any recommendations?

acpi window-manager xubuntu

1 Answers

  1. Best Answer

    I have in /etc/udev/rules.d/80-monitor.rules

    ACTION=="change", SUBSYSTEM=="drm", ENV{HOTPLUG}=="1", ENV{DEVNAME}=="dri/card0", RUN+="/etc/udev/monitors.sh"

    Then in /etc/udev/monitors.sh (marked executable):

    #!/bin/sh
set -e

export DISPLAY=:0
export XAUTHORITY=$(getent passwd $(w -h -s|awk '$3==":0"{print $1}'|sed 1q)|cut -d: -f6)/.Xauthority

desktop() {
    xrandr --output LVDS1 --off || true
    xrandr --output HDMI3 --auto --primary --output HDMI2 --auto --right-of HDMI3
}

laptop() {
    xrandr --output HDMI3 --off || true
    xrandr --output HDMI2 --off || true
    xrandr --output LVDS1 --auto
}

if xrandr|grep -q 'HDMI2 connected'; then
    desktop
else
    laptop
fi

    Some hints and catches with this example:

    1. It only works for the first graphically logged in user.
    2. You'll need to tune the script to match your monitor setup. See the xrandr manpage for help with this.
    3. I'm not sure if the udev rule will match everyone's monitor status change event. I used udevadm monitor --property to figure out what to use.
    4. I had to use --off to turn off all displays explicitly first before reconfiguring before xrandr allowed me to configure new ones. I think this is driver-dependent and not well documented.
    5. I'm using the presence of the external screen to decide which way round to reconfigure. This might not work for everyone.
    6. xrandr sets some resolution by default which was optimal for me. See the manpage for details on how to set custom resolutions if you need.
    • 2