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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

Optional USE flags for x11-misc/lightdm:
USE flag (what is that?) Default Recommended Description
gtk Yes Pull in the gtk+ greeter
introspection Yes Use dev-libs/gobject-introspection for introspection
kde No Pull in the kde greeter
qt4 Yes Add support for the Qt GUI/Application Toolkit version 4.x
razor No Pull in the razorqt greeter


Install lightdm:

root #emerge --ask x11-misc/lightdm


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

  • /etc/lightdm/lightdm.conf





The LightDM KDE greeter also provides a KCM (KDE Control Module), which appears in the System Settings under System AdministrationLogin Screen (LightDM).

Due to LightDM currently assuming GTK+ greeter as the default, if the KDE greeter is requested, it needs to be specified in the /etc/lightdm/lightdm.conf file:

FILE /etc/lightdm/lightdm.conf


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:

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


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.