SDDM - ArchWiki

# SDDM

From ArchWiki

Related articles

- Display manager
- KDE

The Simple Desktop Display Manager (SDDM) is the preferred display manager for KDE Plasma desktop. From Wikipedia:

  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.

## Installation

Install the sddm package.

Then follow Display manager#Loading the display manager to start SDDM at boot.

## Configuration

The configuration file for SDDM can be found at `/etc/sddm.conf`. See sddm.conf(5) 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

### Autologin

SDDM supports automatic login through its configuration file, for example:

    /etc/sddm.conf

    [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 `/usr/share/xsessions/` directory.

An option to autologin into KDE Plasma while simultaneously locking the session is not available [1]

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

See KDE Wallet#Unlock KDE Wallet automatically on login.

### Theme settings

Theme settings can be changed in the `[Theme]` section.

Set to `breeze` for the default Plasma theme.

Some themes are available in the AUR, for example archlinux-themes-sddmAUR.

#### Current theme

Set the current theme through the `Current` value, e.g. `Current=archlinux-simplyblack`.

#### Editing themes

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.

Note: This is just a preview. In this mode, some actions like shutdown, suspend or login will have no effect.

#### Mouse cursor

To set the mouse cursor theme, set `CursorTheme` to your preferred cursor theme.

Valid Plasma mouse cursor theme names are `breeze_cursors`, `Breeze_Snow` and `breeze-dark`.

#### 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:

    /etc/sddm.conf

    [Theme]
    FacesDir=/var/lib/AccountsService/icons/

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.

Note: If avatar images are symlinks, you need to set proper file permissions to the target files.

### Numlock

If you want to enforce Numlock to be enabled, set `Numlock=on` in the `[General]` section.

### Rotate display

See Xrandr#Configuration.

### Configuration GUI

- KDE Frameworks' System Settings contains an SDDM configuration module. Install sddm-kcm package to use it.
- There is a Qt-based sddm-config-editor-gitAUR in the AUR.

### DPI settings

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.

For example:

    /etc/sddm.conf

    [X11]
    ServerArguments=-nolisten tcp -dpi 94

## Troubleshooting

### Hangs after login

Try removing `~/.Xauthority`.

### 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 `sddm.conf`:

    /etc/sddm.conf

    [X11]
    ...
    MinimumVT=7
    ...

### One or more users do not show up on the greeter

Warning: Users set with a lower or higher `UID` range 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):

    /etc/sddm.conf

    [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 `~/.face.icon` or `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

See SDDM README: No User Icon.

### Screen resolution is too low

Issue may be caused by HiDPI usage for monitors with corrupted EDID: [2]

Try disabling HiDPI in `sddm.conf`:

    /etc/sddm.conf

    [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:

    /etc/X11/xorg.conf.d/90-monitor.conf

    Section "Monitor"
            Identifier      "<default monitor>"
            DisplaySize     345 194 # in millimeters
    EndSection

### SDDM takes long time to load when your home directory is encrypted

See Dm-crypt/Mounting at login#SDDM.

Categories:

- KDE
- Display managers