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LightDM is a cross-desktop display manager whose aim is to be the standard display manager for the X server.

The key features (as listed by upstream) include:

  • A well-defined greeter API allowing multiple GUIs.
  • Support for all display manager use cases, with plugins where appropriate.
  • Low code complexity.
  • Fast performance.


USE flags

USE flags for x11-misc/lightdm A lightweight display manager

audit Enable support for Linux audit subsystem using sys-process/audit
elogind Enable session tracking via sys-auth/elogind
gnome Add GNOME support
gtk Pull in the gtk+ greeter
introspection Add support for GObject based introspection
non-root Use non-root user by default
qt5 Add support for the Qt 5 application and UI framework
systemd Enable use of systemd-specific libraries and features like socket activation or session tracking
vala Enable bindings for dev-lang/vala


Install lightdm:

root #emerge --ask x11-misc/lightdm


The (global) configuration file for LightDM can be found at:

  • /etc/lightdm/lightdm.conf


The GTK+ greeter configuration can be modified by manually editing the following file:



The RazorQt greeter currently does not offer any configuration options.

Boot service


Set LightDM as the default display manager:

FILE /etc/conf.d/xdm

To start LightDM on boot, add dbus and xdm to the default runlevel. dbus is necessary because LightDM depends on it to pass messages:

root #rc-update add dbus default
root #rc-update add xdm default

To start LightDM now:

root #/etc/init.d/dbus start
root #/etc/init.d/xdm start


To start LightDM on boot:

root #systemctl enable lightdm

To start LightDM now:

root #systemctl start lightdm

Command-line tool

LightDM includes a command-line tool, dm-tool, which can be used to switch user sessions, lock the current seat, etc. To see a list of available commands, use the --help option:

user $dm-tool --help

For example, to lock the current seat:

user $dm-tool lock


Running commands at log-in

A user can run some programs automatically when logging in using LightDM by adding commands in ~/.xprofile, which will be sourced by LightDM. For example:

FILE ~/.xprofile
# Starting redshift, setting the dpi with xrandr and set the brightness to 50% with xbacklight
xrandr --dpi 192 &
redshift-gtk &
xbacklight -set 50 &

Unlock GNOME Keyring

To unlock your GNOME Keyring (gnome-base/gnome-keyring) automatically on login, edit /etc/pam.d/lightdm to look as follows. Note: Lines ending with the comment #keyring should be added.

FILE /etc/pam.d/lightdm
auth	   include	system-local-login
auth       optional #keyring
account    include	system-local-login
session	   include	system-local-login
session    optional auto_start #keyring


Cursor themes not working

As of March 28, 2015, the stable versions of lightdm (lightdm-1.10.3) and lightdm-gtk-greeter (lightdm-gtk-greeter-1.7.0) have a bug that affects some DEs such as XFCE with setting the mouse cursor. Applications will apply the new mouse theme, but the root window where the window manager draws on does not. To get around this, simply unmask the latest versions (lightdm-1.13.2 and lightdm-gtk-greeter-2.0.0 at the time of writing) and the cursors will be set correctly.

More information can be found in Ubuntu's bug #1024482.

See also