Display manager

Not to be confused with window manager.

Resources

Wikipedia

A display manager (DM), sometimes known as login manager, presents the user with a graphical login screen to start a GUI session, either X or Wayland.

A display manager is not strictly necessary, X can be started from a shell in a VT, but one can provide extra or useful funtionality.

Available software

Alphabetical list of some display managers in the official Gentoo tree:

Name	Package	Description
CDM (Console Display Manager)	x11-misc/cdm	Minimalistic display manager.
GDM (GNOME Display Manager)	gnome-base/gdm	DM often used with GNOME, for Wayland or X.
GreetD	gui-apps/gtkgreet gui-apps/tuigreet	System login and authentication daemon designed for Wayland.
LightDM (Lightweight Display Manager)	x11-misc/lightdm	Cross-desktop display manager aiming to be the standard display manager for X.
LXDM (LXDE Display Manager)	lxde-base/lxdm	LXDE Display Manager.
Qingy (Qingy Is Not GettY)	sys-apps/qingy	A DirectFB getty replacement.
SDDM (Simple Desktop Display Manager)	x11-misc/sddm	Modern display manager for X11 and Wayland aiming to be fast, simple and beautiful.
SLiM (Simple Login Manager)	x11-misc/slim	Desktop-independent graphical display manager, fast with only a few dependencies.
WDM (WINGs Display Manager)	x11-misc/wdm	Modification of XDM.
XDM (X Display Manager)	x11-apps/xdm	X.Org's DM.

Warning
Before setting up and using a display manager, be sure that the chosen GUI environment, startx or Wayland, works without problems. If something does not work refer to the troubleshooting guides, such as Xorg/Guide.

Configuration

In all major Linux operating systems, display managers are started automatically on boot. In order for this to happen automatically a script must be added to the init system's appropriate runlevel. Examples for OpenRC and systemd are provided below.

OpenRC

Under most circumstances, the OpenRC init system (Gentoo's default init system) will be used to start the display manager. The following examples will set SDDM as the display manager, adjust as necessary for other display managers.

Historically, the xdm init script handled the starting of the display manager, which has now been deprecated in favor of the display-manager init script from gui-libs/display-manager-init, jump to next section for a sytem still using xdm.

If gui-libs/display-manager-init is not present, emerge it with:

root #emerge --ask gui-libs/display-manager-init

The configuration file should be modified to use SDDM:

FILE /etc/conf.d/display-managerSet SDDM as the display manager

CHECKVT=7
DISPLAYMANAGER="sddm"

To start the chosen display manager on boot, add the display-manager to the system's default runlevel:

root #rc-update add display-manager default

To start the display-manager immediately, run:

root #rc-service display-manager start

Historical use of the deprecated xdm init script

FILE /etc/conf.d/xdmSet SDDM as the display manager

CHECKVT=7
DISPLAYMANAGER="sddm"

To start the chosen display manager on boot, add the xdm to the system's default runlevel:

root #rc-update add xdm default

To start SDDM immediately, run:

root #rc-service xdm start

systemd

If using systemd as the init system, first locate the chosen <display-manager>.service file.

To start SDDM on boot, enable the service:

root #systemctl enable sddm.service

To start SDDM immediately, run:

root #systemctl start sddm.service

See also

• Xorg/Guide — explains what Xorg is, how to install it, and the various configuration options.
• X without Display Manager — describes how to start an X11 session without a display manager
• Window manager — manages the creation, manipulation, and destruction of on-screen windows and window decorations in X11.
• Desktop environment — provides a list of desktop environments available in Gentoo.
• Login — a primer which explains various aspects of a login shell.