configure_displays should be ran here:

* On resume from suspend
* On key press from window manager (shortcut) -- currently $mod+p in ~/.i3/config
* On login startup -- currently ~/.i3/startup

The simple /etc/pm/sleep.d/50_configure-displays script:
----
#!/bin/sh

# Configure displays on resume and thaw

case "$1" in
	resume|thaw)
		/usr/local/bin/configure_displays
		;;
esac
----