Questions[sddm](ubuntu)

I've searched extensively and there are many mentions of this problem but it seems only a few disparate users have had it over the last few months. But the 3 Kubuntu systems I upgraded to 20.10 all have it now, so I'm surprised it's not a critical bug with already a solution.

Description:

• 'switch user' is gone from the K / Leave menu
• 'Switch user' is gone from SDDM lock screen (you can only re-enter your own locked session). Shutdown / reboot is also gone from lock screen.
• Maybe unrelated: when logging out some users (always the same ones), I get a black screen (for others I go back to a normal sddm screen with user selection). This is not related to the kde_settings.conf / MinimumUid issue

Out systems are family-shared, so it's really annoying. If the lock screen is on, the system has to be forcefully rebooted for another user to use it, with all the disk corruption risks involved.

Here's the result on one of the 3 systems. I don't see any smoking gun in it:

$ journalctl --since "2020-12-25" -u sddm | sed -e "s/.* systemname //"
-- Logs begin at Tue 2019-12-10 19:42:43 CET, end at Sun 2021-01-10 12:09:49 CET. --
systemd[1]: Starting Simple Desktop Display Manager...
systemd[1]: Started Simple Desktop Display Manager.
sddm[2035]: Initializing...
sddm[2035]: Starting...
sddm[2035]: Logind interface found
sddm[2035]: Adding new display on vt 1 ...
sddm[2035]: Loading theme configuration from ""
sddm[2035]: Display server starting...
sddm[2035]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{2eab554e-43ae-4c2b-8751-b3bea3a04ef0} -background none -noreset -displayfd 17 -seat seat0 vt1
sddm[2035]: Setting default cursor
sddm[2035]: Running display setup script  "/usr/share/sddm/scripts/Xsetup"
sddm[2035]: Display server started.
sddm[2035]: Socket server starting...
sddm[2035]: Socket server started.
sddm[2035]: Loading theme configuration from "/usr/share/sddm/themes/ubuntu-theme/theme.conf"
sddm[2035]: Greeter starting...
sddm[2035]: Adding cookie to "/var/run/sddm/{2eab554e-43ae-4c2b-8751-b3bea3a04ef0}"
sddm-helper[2353]: [PAM] Starting...
sddm-helper[2353]: [PAM] Authenticating...
sddm-helper[2353]: [PAM] returning.
sddm-helper[2353]: pam_unix(sddm-greeter:session): session opened for user sddm by (uid=0)
sddm[2035]: Greeter session started successfully
sddm[2035]: Message received from greeter: Connect
sddm[2035]: Message received from greeter: Login
sddm[2035]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[2035]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[2035]: Session "plasma.desktop" selected, command: "/usr/bin/startplasma-x11"
sddm-helper[2424]: [PAM] Starting...
sddm-helper[2424]: [PAM] Authenticating...
sddm-helper[2424]: [PAM] Preparing to converse...
sddm-helper[2424]: [PAM] Conversation with 1 messages
sddm-helper[2424]: gkr-pam: unable to locate daemon control file
sddm-helper[2424]: gkr-pam: stashed password to try later in open session
sddm-helper[2424]: [PAM] returning.
sddm-helper[2424]: pam_kwallet5(sddm:auth): (null): pam_sm_authenticate
sddm[2035]: Authenticated successfully
sddm-helper[2424]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
sddm-helper[2424]: pam_unix(sddm:session): session opened for user dargaud by (uid=0)
sddm[2035]: Auth: sddm-helper exited successfully
sddm[2035]: Greeter stopped.
sddm-helper[2424]: gkr-pam: gnome-keyring-daemon started properly and unlocked keyring
sddm-helper[2424]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
sddm-helper[2424]: Starting: "/etc/sddm/Xsession \"/usr/bin/startplasma-x11\""
sddm[2035]: Session started
sddm[2035]: Authentication error: "Process crashed"
sddm[2035]: Auth: sddm-helper crashed (exit code 15)
sddm[2035]: Authentication error: "Process crashed"
sddm[2035]: Auth: sddm-helper exited with 15
sddm[2035]: Socket server stopping...
sddm[2035]: Socket server stopped.
sddm[2035]: Display server stopping...
systemd[1]: Stopping Simple Desktop Display Manager...
sddm[2035]: Display server stopped.
sddm[2035]: Running display stop script  "/usr/share/sddm/scripts/Xstop"
sddm[2035]: Removing display ":0" ...
sddm[2035]: Adding new display on vt 1 ...
sddm[2035]: Loading theme configuration from ""
sddm[2035]: Display server starting...
sddm[2035]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{5d343de6-e3c5-4c04-8659-a45f6125ce5f} -background none -noreset -displayfd 18 -seat seat0 vt1
sddm[2035]: Setting default cursor
sddm[2035]: Running display setup script  "/usr/share/sddm/scripts/Xsetup"
sddm[2035]: Display server started.
sddm[2035]: Socket server starting...
sddm[2035]: Socket server started.
sddm[2035]: Loading theme configuration from "/usr/share/sddm/themes/ubuntu-theme/theme.conf"
sddm[2035]: Greeter starting...
sddm[2035]: Adding cookie to "/var/run/sddm/{5d343de6-e3c5-4c04-8659-a45f6125ce5f}"
sddm[2035]: Signal received: SIGTERM
sddm[2035]: Socket server stopping...
sddm[2035]: Socket server stopped.
sddm[2035]: Display server stopping...
sddm-helper[9047]: [PAM] Starting...
sddm-helper[9047]: [PAM] Authenticating...
sddm-helper[9047]: [PAM] returning.
sddm[2035]: Display server stopped.
sddm[2035]: Running display stop script  "/usr/share/sddm/scripts/Xstop"
sddm[2035]: QProcess: Destroyed while process ("/usr/lib/x86_64-linux-gnu/sddm/sddm-helper") is still running.
systemd[1]: sddm.service: Succeeded.
systemd[1]: Stopped Simple Desktop Display Manager.
-- Reboot --
systemd[1]: Starting Simple Desktop Display Manager...
systemd[1]: Started Simple Desktop Display Manager.
sddm[1934]: Initializing...
sddm[1934]: Starting...
sddm[1934]: Logind interface found
sddm[1934]: Adding new display on vt 1 ...
sddm[1934]: Loading theme configuration from ""
sddm[1934]: Display server starting...
sddm[1934]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{d57df6b7-2776-4dc6-b28b-1746e9a6613d} -background none -noreset -displayfd 17 -seat seat0 vt1
sddm[1934]: Setting default cursor
sddm[1934]: Running display setup script  "/usr/share/sddm/scripts/Xsetup"
sddm[1934]: Display server started.
sddm[1934]: Socket server starting...
sddm[1934]: Socket server started.
sddm[1934]: Loading theme configuration from "/usr/share/sddm/themes/ubuntu-theme/theme.conf"
sddm[1934]: Greeter starting...
sddm[1934]: Adding cookie to "/var/run/sddm/{d57df6b7-2776-4dc6-b28b-1746e9a6613d}"
sddm-helper[2206]: [PAM] Starting...
sddm-helper[2206]: [PAM] Authenticating...
sddm-helper[2206]: [PAM] returning.
sddm-helper[2206]: pam_unix(sddm-greeter:session): session opened for user sddm by (uid=0)
sddm[1934]: Greeter session started successfully
sddm[1934]: Message received from greeter: Connect
sddm[1934]: Message received from greeter: Login
sddm[1934]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[1934]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[1934]: Session "plasma.desktop" selected, command: "/usr/bin/startplasma-x11"
sddm-helper[2276]: [PAM] Starting...
sddm-helper[2276]: [PAM] Authenticating...
sddm-helper[2276]: [PAM] Preparing to converse...
sddm-helper[2276]: [PAM] Conversation with 1 messages
sddm-helper[2276]: gkr-pam: unable to locate daemon control file
sddm-helper[2276]: gkr-pam: stashed password to try later in open session
sddm-helper[2276]: [PAM] returning.
sddm-helper[2276]: pam_kwallet5(sddm:auth): (null): pam_sm_authenticate
sddm[1934]: Authenticated successfully
sddm-helper[2276]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
sddm-helper[2276]: pam_unix(sddm:session): session opened for user dargaud by (uid=0)
sddm[1934]: Auth: sddm-helper exited successfully
sddm[1934]: Greeter stopped.
sddm-helper[2276]: gkr-pam: gnome-keyring-daemon started properly and unlocked keyring
sddm-helper[2276]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
sddm-helper[2276]: Starting: "/etc/sddm/Xsession \"/usr/bin/startplasma-x11\""
sddm[1934]: Session started
systemd[1]: Stopping Simple Desktop Display Manager...
sddm[1934]: Signal received: SIGTERM
sddm[1934]: Authentication error: "Process crashed"
sddm[1934]: Auth: sddm-helper crashed (exit code 15)
sddm[1934]: Authentication error: "Process crashed"
sddm[1934]: Auth: sddm-helper exited with 15
sddm[1934]: Socket server stopping...
sddm[1934]: Socket server stopped.
sddm[1934]: Display server stopping...
sddm[1934]: Display server stopped.
sddm[1934]: Running display stop script  "/usr/share/sddm/scripts/Xstop"
sddm[1934]: Removing display ":0" ...
sddm[1934]: Adding new display on vt 1 ...
sddm[1934]: Loading theme configuration from ""
sddm[1934]: Display server starting...
sddm[1934]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{784e9002-ceaa-453f-9bbe-8c596e312df0} -background none -noreset -displayfd 18 -seat seat0 vt1
sddm[1934]: Failed to read display number from pipe
sddm[1934]: Display server failed to start. Exiting
systemd[1]: sddm.service: Main process exited, code=killed, status=6/ABRT
systemd[1]: sddm.service: Failed with result 'signal'.
systemd[1]: Stopped Simple Desktop Display Manager.
systemd[1]: sddm.service: Triggering OnFailure= dependencies.
systemd[1]: sddm.service: Failed to enqueue OnFailure= job, ignoring: Transaction for plymouth-quit.service/start is destructive (systemd-tmpfiles-setup-dev.service has 'stop' job queued, but 'start' is included in transaction).
-- Reboot --
systemd[1]: Starting Simple Desktop Display Manager...
systemd[1]: Started Simple Desktop Display Manager.
sddm[2066]: Initializing...
sddm[2066]: Starting...
sddm[2066]: Logind interface found
sddm[2066]: Adding new display on vt 1 ...
sddm[2066]: Loading theme configuration from ""
sddm[2066]: Display server starting...
sddm[2066]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{f4e5de63-9bec-4555-b1c8-b622830fff8f} -background none -noreset -displayfd 17 -seat seat0 vt1
sddm[2066]: Setting default cursor
sddm[2066]: Running display setup script  "/usr/share/sddm/scripts/Xsetup"
sddm[2066]: Display server started.
sddm[2066]: Socket server starting...
sddm[2066]: Socket server started.
sddm[2066]: Loading theme configuration from "/usr/share/sddm/themes/ubuntu-theme/theme.conf"
sddm[2066]: Greeter starting...
sddm[2066]: Adding cookie to "/var/run/sddm/{f4e5de63-9bec-4555-b1c8-b622830fff8f}"
sddm-helper[2344]: [PAM] Starting...
sddm-helper[2344]: [PAM] Authenticating...
sddm-helper[2344]: [PAM] returning.
sddm-helper[2344]: pam_unix(sddm-greeter:session): session opened for user sddm by (uid=0)
sddm[2066]: Greeter session started successfully
sddm[2066]: Message received from greeter: Connect
sddm[2066]: Message received from greeter: Login
sddm[2066]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[2066]: Reading from "/usr/share/xsessions/plasma.desktop"
sddm[2066]: Session "plasma.desktop" selected, command: "/usr/bin/startplasma-x11"
sddm-helper[2414]: [PAM] Starting...
sddm-helper[2414]: [PAM] Authenticating...
sddm-helper[2414]: [PAM] Preparing to converse...
sddm-helper[2414]: [PAM] Conversation with 1 messages
sddm-helper[2414]: gkr-pam: unable to locate daemon control file
sddm-helper[2414]: gkr-pam: stashed password to try later in open session
sddm-helper[2414]: [PAM] returning.
sddm-helper[2414]: pam_kwallet5(sddm:auth): (null): pam_sm_authenticate
sddm[2066]: Authenticated successfully
sddm-helper[2414]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
sddm-helper[2414]: pam_unix(sddm:session): session opened for user dargaud by (uid=0)
sddm[2066]: Auth: sddm-helper exited successfully
sddm[2066]: Greeter stopped.
sddm-helper[2414]: gkr-pam: gnome-keyring-daemon started properly and unlocked keyring
sddm-helper[2414]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
sddm-helper[2414]: Starting: "/etc/sddm/Xsession \"/usr/bin/startplasma-x11\""
sddm[2066]: Session started

2021 update: after the upgrade to kubuntu 21.10, it finally worked as expected for a few weeks... until some update thrashed that. Now using the Switch User option leads to a black screen you can't recover from. I can still use Ctrl-Alt-F2 to kill and restart plasma, but it's bad. Will post more when I have time to gather data.

I have recently installed KDE 5 (kde-plasma-desktop) on Ubuntu 20.04, and as part of the installation, it asked me to switch the login screen manager to sddm.

When sddm starts (either on boot, or after logging out) it blocks the screen with a large on-screen keyboard (the rest of the screen is black), and I cannot get rid of the keyboard without clicking the "hide keyboard" 'key' with the mouse, after which the sddm login screen appears. Although I can understand that there might be accessibility reasons for this, I can see no way to switch this off (I am the only user of this computer), so it is rather annoying.

Is there a way to prevent this on-screen keyboard from appearing unrequested, or, alternatively, would KDE actually work quite happily with gdm3 as the login screen manager (or another manager, such as lightdm) instead?

I would like to display an image of my choice instead of the grey icon above my username on the login screen:

No doubt there is a setting for this somewhere, but I have failed to find it so far.

How do I change user images in the SDDM greeter?

_{Useful for testing -- you can use this command to preview the login screen without logging out.}

OP on reddit

Hi,

I have a problem with Kubuntu 19.04 in my 13" FHD (1920x1080) laptop screen. The login screen is too small as was the whole Plasma KDE.

I was able to re-scale the screen to 1.5 (150%) and now Plasma KDE looks great but the login screen still remains small (FHD scaled) though when I come back from Suspend mode the login screen do re-scales to 150%.

There is no file called sddm.conf under /etc/, as written in the project's github page, in my OS sddm.conf located under /etc/init.

I have added the lines

[X11]
ServerArguments=-nolisten tcp -dpi 144

At beginning of /etc/init/sddm.conf where 144 represents my base resolution in DPI as written in the X-Server information * 1.5 but still it doesn't fix the login screen resolution scale.

Any suggestions will be gladly welcomed.

TNX

After I switch to virtual console using Ctrl+Alt+F6 I could not get back to X session using Ctrl+Alt+F7 - only blinking cursor is shown. Tried chvt - same result. Have to reboot and lost all my opened apps which is very inconvenient. Kubuntu version is 18.04 Bionic.

Could anybody help?