Difference between revisions of "SDDM"
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== Troubleshooting ==
== Troubleshooting ==
=== Hangs after login ===
=== Hangs after login ===
Revision as of 00:46, 9 January 2018
- Simple Desktop Display Manager (SDDM) is a display manager (a graphical login program) for X11 and Wayland windowing systems. SDDM was written from scratch in C++11 and supports theming via QML. KDE chose SDDM to be the successor of the KDE Display Manager for KDE Plasma 5.
- 1 Installation
- 2 Configuration
- 3 Troubleshooting
- 3.1 SDDM still runs on Xorg
- 3.2 Hangs after login
- 3.3 SDDM starts on tty1 instead of tty7
- 3.4 One or more users do not show up on the greeter
- 3.5 SDDM loads only US keyboard layout
- 3.6 No user Icon
- 3.7 Screen resolution is too low
- 3.8 SDDM takes long time to load when your home directory is encrypted
Install the package.
Then follow Display manager#Loading the display manager to start SDDM at boot.
The configuration file for SDDM can be found at
/etc/sddm.conf. See for all options.
On systems controlled by systemd, everything should work out of the box, since SDDM defaults to using
systemd-logind for session management. The configuration file will therefore not be created at package installation time. SDDM offers a command for generating a sample configuration file with the default settings if you really want one:
# sddm --example-config > /etc/sddm.conf
SDDM supports automatic login through its configuration file, for example:
[Autologin] User=john Session=plasma.desktop
This configuration causes a KDE Plasma session to be started for user
john when the system is booted. Available session types can be found in
An option to autologin into KDE Plasma while simultaneously locking the session is not available 
You can add a script that activates the screensaver of KDE to the autostart as a workaround:
#!/bin/bash /usr/bin/qdbus-qt4 org.kde.screensaver /ScreenSaver SetActive true & exit 0
Unlock KDE Wallet automatically on login
Theme settings can be changed in the
breeze for the default Plasma theme.
Some themes are available in the AUR, for example AUR.
Set the current theme through the
Current value, e.g.
The default SDDM theme directory is
/usr/share/sddm/themes/. You can add your custom made themes to that directory under a separate subdirectory. Note that SDDM requires these subdirectory names to be the same as the theme names. Study the files installed to modify or create your own theme.
Testing (Previewing) a Theme
You can preview an SDDM theme if needed. This is especially helpful if you are not sure how the theme would look if selected or just edited a theme and want to see how it would look without logging out. You can run something like this:
$ sddm-greeter --theme /usr/share/sddm/themes/breeze
This should open a new window and show a preview of the theme.
To set the mouse cursor theme, set
CursorTheme to your preferred cursor theme.
Valid Plasma mouse cursor theme names are
Changing your avatar
You can simply put a png image named
username.face.icon into the default directory
/usr/share/sddm/faces/. Alternatively you can change the default directory to match your desires:
You can also put a png image named
.face.icon at the root of your home directory. However, you need to make sure that
sddm user can read that file.
If you want to enforce Numlock to be enabled, set
Numlock=on in the
- KDE Frameworks' System Settings contains an SDDM configuration module. Install package to use it.
- There is a Qt-based AUR in the AUR.
Sometimes it is useful to set up correct monitor's PPI settings on a "Display Manager" level. To do so you need to find "ServerArguments" parameter in sddm.conf and add -dpi %YOUR RESOLUTION at the end of the string.
[X11] ServerArguments=-nolisten tcp -dpi 94
SDDM still runs on Xorg
SDDM currently cannot run on a Wayland session because it still does not support this feature. Having a full Wayland system is still not possible with SSDM. For now SDDM is rather a QML based display manager for X11 and Wayland *sessions*.
Hangs after login
SDDM starts on tty1 instead of tty7
SDDM follows the systemd convention of starting the first graphical session on tty1. If you prefer the old convention where tty1 through tty6 are reserved for text consoles, uncomment and edit the
MinimumVT variable, under the
[X11] section in
[X11] ... MinimumVT=7 ...
One or more users do not show up on the greeter
UIDrange should generally not be exposed to a Display manager.
SDDM only displays users with a UID in the range of 1000 to 65000 by default, if the UIDs of the desired users are below this value then you will have to modify this range. Modify your
sddm.conf to (for a UID of 501, say):
[Users] HideShells=/sbin/nologin,/bin/false # Hidden users, this is if any system users fall within your range, see /etc/passwd on your system. HideUsers=git,sddm,systemd-journal-remote,systemd-journal-upload # Maximum user id for displayed users MaximumUid=65000 # Minimum user id for displayed users MinimumUid=500 #My UID is 501
SDDM loads only US keyboard layout
SDDM loads the keyboard layout specified in
/etc/X11/xorg.conf.d/00-keyboard.conf. You can generate this configuration file by
localectl set-x11-keymap command. See Keyboard configuration in Xorg for more information.
No user Icon
SDDM reads user icon from either
FacesDir/username.face.icon. The user icon must be saved in PNG format.
You need to make sure that SDDM user have permissions to read those files.
$ setfacl -m u:sddm:x /home/username $ setfacl -m u:sddm:r /home/username/.face.icon
Screen resolution is too low
Issue may be caused by HiDPI usage for monitors with corrupted EDID: 
Try disabling HiDPI in
[General] # Enable Qt's automatic high-DPI scaling EnableHiDPI=false
If even the above fails, you can try setting your screen size in a Xorg conf file:
Section "Monitor" Identifier "<default monitor>" DisplaySize 345 194 # in millimeters EndSection