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) are:
- 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 flag (what is that?)||Default||Recommended||Description|
||Yes||Pull in the gtk+ greeter|
||Yes||Use dev-libs/gobject-introspection for introspection|
||No||Pull in the kde greeter|
||Yes||Add support for the Qt GUI/Application Toolkit version 4.x|
||No||Pull in the razorqt greeter|
emerge --ask lightdm
The configuration file for LightDM itself is: /etc/lightdm/lightdm.conf
The LightDM KDE greeter also provides a KCM (KDE Control Module), which appears in the System Settings under System Administration → Login 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:
[SeatDefaults] … greeter-session=lightdm-kde-greeter
The RazorQt greeter currently does not offer any configuration options.
Set LightDM as the default display manager:
To start LightDM on boot, add dbus & xdm to the default runlevel:
rc-update add dbus default
rc-update add xdm default
To start LightDM now:
To start LightDM on boot:
systemctl enable lightdm
To start LightDM now:
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:
For example, to lock the current seat:
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.