Documentation for this is hard to find. Slick-greeter, which installed as apparent dependency after zypper al lightdm-gtk*, does have a man page, but trying to configure via /etc/lightdm/slick-greeter.conf doesn’t seem to have produced any fruit:
background-=#4444AA
background-color=#000000
show-a11y=true
show-hostname=true
show-clock=true
show-quit=true
xft-dpi=143
enable-hidpi=off
After creating this, the greeter screen didn’t paint anything but a text cursor until I rebooted, upon which I found none of these settings had any effect. If https://github.com/canonical/lightdm has appropriate documentation, I’m missing it. man lightdm produces no man page. It would be nice to find some official documentation something like https://www.lesbg.com/jdieter/lightdm.conf. No luck so far. In an Xterm after WINDOWMANAGER=/usr/bin/icewm startx produced the following:
+0.00s] MESSAGE: Using the 'memory' GSettings backend. Your settings will not be saved or shared with other applications.
+0.00s] WARNING: settings.vala:223: Error in apply_conf_settings (): Key file does not start with a group
+0.00s] DEBUG: slick-greeter.vala:569: HiDPI support: auto
Traceback (most recent call last):
File "/usr/bin/slick-greeter-check-hidpi", line 3, in <module>
import gi
ModuleNotFoundError: No module named 'gi'
+0.15s] DEBUG: slick-greeter.vala:601: Launched at-spi-bus-launcher. PID: 0
+0.16s] DEBUG: slick-greeter.vala:610: Starting slick-greeter 1.1.4 UID=0 LANG=POSIX
+0.16s] DEBUG: slick-greeter.vala:613: Setting cursor
+0.16s] DEBUG: slick-greeter.vala:627: Loading command line options
+0.16s] DEBUG: slick-greeter.vala:651: Running in test mode
+0.16s] DEBUG: slick-greeter.vala:654: Setting GTK+ settings
+0.30s] DEBUG: slick-greeter.vala:677: Creating Slick Greeter
+0.30s] DEBUG: slick-greeter.vala:55: Creating background surface
+0.30s] DEBUG: Connecting to display manager...
+0.30s] WARNING: slick-greeter.vala:70: Failed to connect to LightDM daemon: Unable to determine socket to daemon
+0.48s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.48s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.52s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.52s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.53s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.53s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.53s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.53s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.53s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.53s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.54s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.54s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.54s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.54s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.54s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.54s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.55s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.55s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.55s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.55s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.55s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.55s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.55s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.55s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.56s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.56s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.56s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.56s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.56s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.56s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.56s] DEBUG: slick-greeter.vala:209: Invalid session: 'gnome'
+0.56s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.57s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.57s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.57s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.57s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.57s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.57s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.57s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.58s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.58s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.58s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.58s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.58s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.58s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.59s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.59s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.59s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.59s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.59s] WARNING: slick-greeter.vala:198: Could not find a default session.
+0.59s] DEBUG: slick-greeter.vala:216: Using default session: '(null)'
+0.59s] DEBUG: slick-greeter.vala:680: Showing greeter
+0.59s] DEBUG: slick-greeter.vala:293: Showing main window
+0.61s] DEBUG: background.vala:68: Making background #000000 at 800x600,640x480
+0.61s] DEBUG: background.vala:79: Render of background #000000 complete
+0.61s] CRITICAL: gtk_window_resize: assertion 'width > 0' failed
+0.61s] CRITICAL: main_window_move_to_monitor: assertion 'monitor != NULL' failed
+0.65s] DEBUG: slick-greeter.vala:690: Starting main loop
(slick-greeter:14110): Gtk-WARNING **: gtk_widget_size_allocate(): attempt to allocate widget with width 0 and height -32
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
+0.78s] DEBUG: slick-greeter.vala:281: starting system-ready sound
+0.78s] DEBUG: background.vala:68: Making background * at 800x600,640x480
+0.78s] DEBUG: background.vala:159: Error loading background: Failed to open file '*': No such file or directory
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
+0.79s] DEBUG: background.vala:121: Render of background * complete
+0.79s] DEBUG: background.vala:138: images[0] was null for *
+0.79s] DEBUG: background.vala:138: images[1] was null for *
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
(slick-greeter:14110): Gtk-WARNING **: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner GtkBox)
+1.34s] DEBUG: background.vala:567: Regenerating backgrounds
+1.34s] DEBUG: background.vala:68: Making background #000000 at 800x600,640x480
+1.34s] DEBUG: background.vala:79: Render of background #000000 complete
+1.34s] DEBUG: background.vala:68: Making background * at 800x600,640x480
+1.34s] DEBUG: background.vala:159: Error loading background: Failed to open file '*': No such file or directory
+1.40s] DEBUG: background.vala:121: Render of background * complete
+1.40s] DEBUG: background.vala:138: images[0] was null for *
+1.40s] DEBUG: background.vala:138: images[1] was null for *
+9.12s] DEBUG: slick-greeter.vala:693: Cleaning up
+9.12s] DEBUG: slick-greeter.vala:707: Exiting
When I try to login via the greeter as it is, it reports “Failed to start session”.
YaST2 doesn’t seem to have a way to configure lightdm either. 