Display manager

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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

Console

  • CDM — Ultra-minimalistic, yet full-featured login manager written in Bash.
https://github.com/ghost1227/cdm || cdm-gitAUR
  • Console TDM — Extension for xinit written in pure Bash.
https://github.com/dopsi/console-tdm || console-tdmAUR
  • nodm — Minimalistic display manager for automatic logins.
https://github.com/spanezz/nodm || nodm

Graphical

  • Entrance — An EFL based display manager, highly experimental.
http://enlightenment.org/ || entrance-gitAUR
https://wiki.gnome.org/Projects/GDM || gdm
  • KDMKDE4 display manager (discontinued).
http://www.kde.org/ || kdebase-workspaceAUR
  • LightDM — Cross-desktop display manager, can use various front-ends written in any toolkit.
http://www.freedesktop.org/wiki/Software/LightDM || lightdm
  • LXDMLXDE display manager. Can be used independent of the LXDE desktop environment.
http://sourceforge.net/projects/lxdm/ || lxdm
  • MDM — MDM display manager, used in Linux Mint, a fork of GDM 2.
https://github.com/linuxmint/mdm || mdm-display-managerAUR
  • SDDM — QML-based display manager and successor to KDE4's kdm; recommended for Plasma 5 and LXQt.
https://github.com/sddm/sddm || sddm
  • SLiM — Lightweight and elegant graphical login solution. (discontinued)
http://sourceforge.net/projects/slim.berlios/ || slim
  • XDM — X display manager with support for XDMCP, host chooser.
http://www.x.org/archive/X11R7.5/doc/man/man1/xdm.1.html || xorg-xdm

Loading the display manager

To enable graphical login, enable the appropriate systemd service. For example, for SDDM, enable sddm.service.

This should work out of the box. If not, you might have to reset a custom default.target symlink to point to the default graphical.target.

After enabling SDDM a symlink display-manager.service should be set in /etc/systemd/system/. You may need to use --force to override old symlinks.

$ ls -l /etc/systemd/system/display-manager.service
[...] /etc/systemd/system/display-manager.service -> /usr/lib/systemd/system/sddm.service

Using systemd-logind

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

Session configuration

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

Run ~/.xinitrc as a session

Installing xinit-xsessionAUR will provide an option to run your .xinitrc as a session.

Starting applications without a window manager

You can also launch an application without any decoration, desktop, or window management. For example to launch google-chromeAUR create a web-browser.desktop file in /usr/share/xsessions/ like this:

[Desktop Entry]
Encoding=UTF-8
Name=Web Browser
Comment=Use a web browser as your session
Exec=/usr/bin/google-chrome --auto-launch-at-startup
TryExec=/usr/bin/google-chrome --auto-launch-at-startup
Icon=google-chrome

In this case, once you login, the application set with Exec will be launched immediately. When you close the application, you will be taken back to the login manager (same as logging out of a normal DE/WM).

It is important to remember that most graphical applications are not intended to be launched this way and you might have manual tweaking to do or limitations to live with (there is no window manager, so do not expect to be able to move or resize any windows, including dialogs; nonetheless, you might be able to set the window geometry in the application's configuration files).

See also xinitrc#Starting applications without a window manager.

Tips and tricks

Autostarting

Most display managers source /etc/xprofile, ~/.xprofile and /etc/X11/xinit/xinitrc.d/. For more details, see xprofile.

Set the language

Tango-inaccurate.pngThe factual accuracy of this article or section is disputed.Tango-inaccurate.png

Reason: This seems to change the locale of the user session but not of the DM itself. Probably better to link to Locale#Setting the locale. (Discuss in Talk:Display manager#)

For display managers that use AccountsService the display manager locale can be set by editing /var/lib/AccountsService/users/$USER:

[User]
Language=your_locale

where your_locale is a value such as en_GB.UTF-8.

Restart your display manager for the changes to take effect.

Known issues

Incompatibility with systemd

Affected DMs: Entrance, MDM

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.