So, the question is almost in the title: what is the process that makes my display settings change automatically when I plug an external display to my laptop ?
1 Answer
My problem has been fixed by an update of xserver-xorg-video-intel (see https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1505695).
So it seems hotplug management of displays goes that way:
X server driver detects a new monitor. See
man intel
for example, which saysOption "HotPlug" "boolean" This option controls whether the driver automatically notifies applications when monitors are connected or disconnected. default: enabled
this information goes through
randr
to inform applications of the event- applications listening to randr can then take action: specifically,
gnome-settings-daemon
(*) listens to these events, and will change the settings accordingly, using the informations saved in~/.config/monitors.xml
(*) see gsd-xrandr-manager.c