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Simple Desktop Display Manager (SDDM) is a display manager that supports X11 and Wayland.


USE flags

USE flags for x11-misc/sddm Simple Desktop Display Manager

consolekit Use ck-launch-session from sys-auth/consolekit by default in Xsession (no native support) local
elogind Use sys-auth/elogind for session tracking. local
pam Add support for PAM (Pluggable Authentication Modules) - DANGEROUS to arbitrarily flip global
systemd Enable use of systemd-specific libraries and features like socket activation or session tracking global
test Workaround to pull in packages needed to run with FEATURES=test. Portage-2.1.2 handles this internally, so don't set it in make.conf/package.use anymore global


Install x11-misc/sddm:

root #emerge --ask x11-misc/sddm

If there are performance issues, it might help to add the sddm user to the video group:

root #usermod -a -G video sddm


The global configuration file path for SDDM is: /etc/sddm.conf

An example configuration file can be generated in the correct location using the following command:

root #sddm --example-config > /etc/sddm.conf



Set SDDM as the default display manager:

FILE /etc/conf.d/xdm

To start SDDM on boot, add xdm to the default runlevel:

The dbus service gets pulled in dynamically.
root #rc-update add xdm default

To start SDDM now:

root #/etc/init.d/xdm start

After logging in to the X session via sddm, it is a good idea to verify that ConsoleKit is working as intended. By typing ck-list-sessions all active sessions can be listed. The list should include your session, typically running on x11-display-device = '/dev/tty7'. This session should also read active = TRUE. Active being FALSE indicates an issue [1][2].


To start SDDM on boot:

root #systemctl enable sddm.service

To start SDDM now:

root #systemctl start sddm.service


Graphical configuration is integrated in Plasma 5 system settings by installing kde-plasma/sddm-kcm:

root #emerge --ask kde-plasma/sddm-kcm


Permission denied errors in Xorg.log

The X server will not start and permission denied errors (such as the following) are present in the Xorg.log log file:

FILE /var/log/Xorg.log
/var/log/Xorg.0.log:[ 2058.998] (EE) /dev/dri/card0: failed to set DRM interface version 1.4: Permission denied
/var/log/Xorg.0.log:[ 2061.229] (EE) intel(0): [drm] failed to set drm interface version: Permission denied [13].

It is likely the sddm user has not been added to the video group. Running the following command should fix the problem:

root #usermod -a -G video sddm

Missing users

If the login screen is missing some user(s) to choose from, this might be caused by sddm.conf - standard MinimumUid is 1000 and some existing users may have lower Uids.

FILE /etc/sddm.conf

See also

  • LightDM - A cross-desktop display manager used by Ubuntu.
  • SLiM - A desktop-independent graphical display manager.


  1. [SOLVED] xfce4 "shut down" "restart" button are disabled [1]
  2. Hey host, give me a new login please! [2]