A display manager, or login manager, is typically a graphical user interface that is displayed at the end of the boot process in place of the default shell. There are various implementations of display managers, just as there are various types of window managers and desktop environments. There is usually a certain amount of customization and themeability available with each one.
List of display managers
- CDM — Console Display Manager is an ultra-minimalistic, yet full-featured login manager written in bash
- Console TDM — extension for xorg-xinit written in pure bash
- LightDM — Light Display Manager is a cross-desktop display manager, can use various front-ends written in any toolkit.
- MDM — MDM Display Manager, fork of GDM 2
- Qingy — ultralight and very configurable graphical login independent on X Windows (uses DirectFB)
- SDDM — QML-based display manager
- https://github.com/sddm/sddm || AUR, AUR
- SLiM — Simple Login Manager is a lightweight and elegant graphical login solution
- XDM — X Display Manager with support for XDMCP, host chooser.
Loading the display manager
# systemctl enable kdm
This should work out of the box. If not, you might have a default.target set manually or from an older install:
$ ls -l /etc/systemd/system/default.target
/etc/systemd/system/default.target -> /usr/lib/systemd/system/graphical.target
Simply delete the symlink and systemd will use its stock default.target (i.e. graphical.target).
# rm /etc/systemd/system/default.target
After enabling kdm a symlink "display-manager.service" should be set in /etc/systemd/system/
$ ls -l /etc/systemd/system/display-manager.service
/etc/systemd/system/display-manager.service -> /usr/lib/systemd/system/kdm.service
In order to check the status of your user session, you can use
loginctl. All polkit actions like suspending the system or mounting external drives will work out of the box.
$ loginctl show-session $XDG_SESSION_ID
Tips and tricks
Many display managers read available sessions from
/usr/share/xsessions/ directory. It contains standard desktop entry files for each DM/WM.
To add/remove entries to your display manager's session list; create/remove the .desktop files in
/usr/share/xsessions/ as desired. A typical .desktop file will look something like:
[Desktop Entry] Encoding=UTF-8 Name=Openbox Comment=Log in using the Openbox window manager (without a session manager) Exec=/usr/bin/openbox-session TryExec=/usr/bin/openbox-session Icon=openbox.png Type=XSession
Most of display managers sources
/etc/X11/xinit/xinitrc.d/. For more details, see xprofile.
Incompatibility with systemd
Affected DMs: MDM, SDDM, SLiM
Some display managers are not fully compatible with systemd, because they reuse the PAM session process. It causes various problems on second login, e.g.:
- NetworkManager applet does not work,
- PulseAudio volume cannot be adjusted,
- login failed into GNOME with another user.
See the following bugtacker reports for more details: