LightDM
More info
- Creator
- Robert Ancell, Canonical
- Released
- Type
- Display manager
- License
- GPL 3 / LGPL 3
- Source
- github.com/canonical/lightdm
Canonical's display manager from 2010, built so that the login screen is a swappable program — which is how Ubuntu, Mint and the Xfce desktops each ended up with their own greeter on top of the same daemon.
Robert Ancell wrote LightDM at Canonical around a single separation. The daemon does what a display manager must: start the X server, authenticate through PAM, launch the session and handle XDMCP. It draws nothing. The login screen, the greeter, is a separate process that talks to the daemon through the liblightdm library and can be written in any toolkit at all. GDM had just been rewritten into what was effectively a GNOME Shell in disguise, and "light" meant not pulling in the whole of GNOME for a password box.
Ubuntu switched to LightDM in 11.10 in the autumn of 2011 with a Unity greeter, and the ecosystem followed: lightdm-gtk-greeter for the Xfce desktops, Mint's slick-greeter, elementary's own. Guest sessions, multi-seat and a built-in VNC server lived in the daemon. When Ubuntu dropped Unity in 2017 it went back to GDM, but LightDM remains the default in Xubuntu, Linux Mint and elementary OS. The greeter runs on X even when the session it launches is Wayland.