Linux: How to run a script when an external monitor is connected?

Question

How can I detect when an external monitor is connected in linux?

I need to run various scripts to set up my workspace.

Is there some clever way to kick off a script when the monitor state has changed?

I'm using the Nvidia display driver.

Solution 1

There are a set of tools called read-edid that can parse extended display identification data (EDID). If your external monitor is actually detected by these tools, you might be able to periodically check for detection and use the output to start scripts, etc.

You didn't mention though whether you need to do this regardless of whether X was running.

Solution 2

You should use udev events... a possible rule might look like:

KERNEL=="card0", SUBSYSTEM=="drm", ENV{DISPLAY}=":0", ENV{XAUTHORITY}="/home/ninette/.Xauthority", RUN+="/usr/local/bin/0x_hw_hotplug_monitor.sh"

(Source https://bbs.archlinux.org/viewtopic.php?pid=1329375#p1329375)

Solution 3

I was looking for the same answer :/
I'm using disper (http://willem.engen.nl/projects/disper) and gconftool to enable/disable my second monitor together with a second gnome-panel on it.
disper -l lists all connected monitors, so you could poll that as a last resort.

# only primary display
disper -s
gconftool-2 --type int --set  /apps/panel/toplevels/panel_1/screen -- -1


# dual display (nvidia twinview)
disper -e
gconftool-2 --type int --set  /apps/panel/toplevels/panel_1/screen 0
killall gnome-panel

Comments

[new123456]

The hackish way would be to write a script that queries for changes in output in xrandr every couple seconds, and runs the script(s) if it notices a difference.

[Andy]

Ideally you can tell udev to run a script. I don't expect that to work with nvidia drivers until KMS is supported, although I haven't tried. stackoverflow.com/questions/5469828/…