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Chris Burgess
Asked: 2017-12-12 13:25:20 +0800 CST

How can I make Unity display arrangement retain settings

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I move my laptop (ThinkPad T570, Ubuntu Xenial, Unity/Compiz) between different work environments, and I find that using Unity Control Center "Display" applet doesn't reliably (ever?!) retain the arrangements I specify.

To work around this, I've written a bash/xrandr script which arranges things as I want them. (Available here as a gist, but the details aren't really essential to my question so not including in full). If the screens don't appear correctly then I execute this script to arrange them.

What I'd like to do is have this script trigger on monitor connection. Unity/Compiz do this for the settings stored in Display prefs, so I'd like to know the correct way to take my preferred settings as expressed in bash/xrandr, and have that be delivered by Ubuntu as part of the "native" experience.

UPDATE: I found ~/.config/monitors.xml which seems to be where Unity stores the settings. Here's mine, with new revisions as I swap locations.

I've thought about triggering the rearrangement via /etc/udev/rules.d, but that would require permitting scripts run by root to talk to my WM, which presumably means opening xhost permissions. Since the default OS seems to arrange displays without that (just not to an arrangement I want), I'd prefer to find as "native" a solution as possible.

unity

1 Answers

  1. I ended up handling this in a bash script which tests the output of xrandr for connected devices, then sets appropriate per-environment layouts.

    Below is a simplified version which demonstrates how to do it. 

    #!/bin/bash

# Unity doesn't remember my screen layouts, so I made this to do it for me.
# GPLv3+, (c) Chris Burgess @xurizaemon

CONNECTED=$( xrandr | grep ' connected' )

LAYOUT=unknown
if [[ $CONNECTED = *"DP-1 connected"* ]] ; then
  LAYOUT=thunderbolt
elif [[ $CONNECTED = *"HDMI-2 connected"* ]] ; then
  LAYOUT=hdmi-2
fi

case "$LAYOUT" in
  "thunderbolt")
    # Thunderbolt, laptop
    xrandr --output DP-1 --auto --left-of eDP-1 --primary
    echo "Configured for $LAYOUT"
    ;;
  "hdmi-2")
    # Set to 57Hz for monitor support
    xrandr --newmode "1920x1080_57.00"  163.00  1920 2040 2240 2560  1080 1083 1088 1119 -hsync +vsync
    xrandr --addmode HDMI-2 "1920x1080_57.00"
    # HDMI, laptop
    xrandr --output HDMI-2 --mode "1920x1080_57.00" --left-of eDP-1 --primary
    echo "Configured for $LAYOUT"
    ;;
  *)
    echo "Layout $LAYOUT not known."
esac

    My actual script is available at https://gist.github.com/e1892192ea8dd03a210d2890f8f966e7

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