Background briefly shows and plasma crashes: Plasmashell version 5.27.12

Centurion030 · September 24, 2026, 5:29am

Okay,

I had upgrades today, and the reboot went without a problem. However, later I tried to lock the screen before a trip and there was issues.

Rebooting and logging back in only showed the background before crashing plasma. I am accessing the system from my backup laptop.

Notes from the KDE facebook page:
Okay. I have a Kubuntu 24.04 system. The main tower got updated today. When I was leaving to go on a trip, the usual screen lock failed and it mentioned loginctl commands. I have had issues trying to get the background screen back. I am typing this from my backup laptop.

I have reinstalled a bunch of applications per other notes via google. The background briefly appears and then goes away. Help!!!

When I ssh into the tower:
centurion030@james-precisiontower7910:~$ sudo su -
[sudo] password for centurion030:
root@james-precisiontower7910:~# apt-get update
Hit:1 Index of /ubuntu noble InRelease
Hit:2 https://dl.google.com/linux/chrome-stable/deb stable InRelease
Hit:3 Index of /ubuntu noble-updates InRelease
Hit:4 Index of /ubuntu noble-security InRelease
Hit:5 Index of /ubuntu noble-backports InRelease
Hit:6 Index of /tomtomtom/yt-dlp/ubuntu noble InRelease
Hit:7 Index of /opera-stable/ stable InRelease
Hit:8 https://ppa.launchpadcontent.net/zhangso.../fastfetch/ubuntu noble InRelease
Reading package lists… Done
root@james-precisiontower7910:~# apt-get dist-upgrade
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
Calculating upgrade… Done
The following upgrades have been deferred due to phasing:
apparmor dmidecode libapparmor1 libaudit-common libaudit1 libpciaccess0 libpciaccess0:i386 libvirt-clients libvirt-daemon libvirt-daemon-config-network
libvirt-daemon-config-nwfilter libvirt-daemon-driver-qemu libvirt-daemon-system libvirt-daemon-system-systemd libvirt-l10n libvirt0 xserver-common xserver-xorg-core
xserver-xorg-legacy
0 upgraded, 0 newly installed, 0 to remove and 19 not upgraded.
root@james-precisiontower7910:~#

error text file:

enturion030@james-precisiontower7910:~$ cat errors.txt

centurion030@james-precisiontower7910:~$ plasmashell --replace &

[1] 11407

centurion030@james-precisiontower7910:~$ Checking screens: available: (QScreen(0x5cb1e06079b0, name=“DP-0”), QScreen(0x5cb1e0607aa0, name=“DVI-I-1”)) redundant: QHash() fake: QSet() all: (QScreen(0x5cb1e06079b0, name=“DP-0”), QScreen(0x5cb1e0607aa0, name=“DVI-I-1”))

Checking screens: available: (QScreen(0x5cb1e06079b0, name=“DP-0”), QScreen(0x5cb1e0607aa0, name=“DVI-I-1”)) redundant: QHash() fake: QSet() all: (QScreen(0x5cb1e06079b0, name=“DP-0”), QScreen(0x5cb1e0607aa0, name=“DVI-I-1”))

kf.plasma.quick: Applet preload policy set to 1

file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/templates/InlineMessage.qml:265:13: QML SelectableLabel: Binding loop detected for property “implicitWidth”

QObject::connect: No such slot DesktopProtocol::_k_slotRedirection(KIO::Job *, QUrl)

Trying to use rootObject before initialization is completed, whilst using setInitializationDelayed. Forcing completion

org.kde.plasma.kicker: Entry is not valid “org.kde.kontact.desktop” QSharedPointer(0x5cb1e1d0c760)

org.kde.plasma.kicker: Entry is not valid “org.kde.kontact.desktop” QSharedPointer(0x5cb1e197df20)

Cyclic dependency detected between “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml” and “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/NotificationHeader.qml”

Cyclic dependency detected between “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml” and “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/ThumbnailStrip.qml”

file:///usr/share/plasma/plasmoids/org.kde.plasma.networkmanagement/contents/ui/main.qml:95: TypeError: Cannot read property ‘airplaneModeAvailable’ of null

file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/plasma/extras/PlaceholderMessage.qml:238:5: QML Heading: Binding loop detected for property “verticalAlignment”

KCrash: Attempting to start /usr/bin/plasmashell

KCrash: crashing… crashRecursionCounter = 2

KCrash: Application Name = plasmashell path = /usr/bin pid = 11407

KCrash: Arguments: /usr/bin/plasmashell --replace

KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi

Checking screens: available: (QScreen(0x5e3f21423410, name=“DP-0”), QScreen(0x5e3f21423500, name=“DVI-I-1”)) redundant: QHash() fake: QSet() all: (QScreen(0x5e3f21423410, name=“DP-0”), QScreen(0x5e3f21423500, name=“DVI-I-1”))

QSocketNotifier: Invalid socket 7 and type ‘Read’, disabling…

QSocketNotifier: Invalid socket 26 and type ‘Read’, disabling…

QSocketNotifier: Invalid socket 28 and type ‘Read’, disabling…

QSocketNotifier: Invalid socket 31 and type ‘Read’, disabling…

kf.plasma.quick: Applet preload policy set to 1

file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/templates/InlineMessage.qml:265:13: QML SelectableLabel: Binding loop detected for property “implicitWidth”

QObject::connect: No such slot DesktopProtocol::_k_slotRedirection(KIO::Job *, QUrl)

Trying to use rootObject before initialization is completed, whilst using setInitializationDelayed. Forcing completion

org.kde.plasma.kicker: Entry is not valid “org.kde.kontact.desktop” QSharedPointer(0x5e3f22b1dad0)

org.kde.plasma.kicker: Entry is not valid “org.kde.kontact.desktop” QSharedPointer(0x5e3f22b1d4e0)

Cyclic dependency detected between “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml” and “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/NotificationHeader.qml”

Cyclic dependency detected between “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml” and “file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/ThumbnailStrip.qml”

file:///usr/share/plasma/plasmoids/org.kde.plasma.networkmanagement/contents/ui/main.qml:95: TypeError: Cannot read property ‘airplaneModeAvailable’ of null

file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/plasma/extras/PlaceholderMessage.qml:238:5: QML Heading: Binding loop detected for property “verticalAlignment”

file:///usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/kirigami.2/ContextDrawer.qml:135:9: QML ListView: Binding loop detected for property “topMargin”

Unable to start Dr. Konqi

Re-raising signal for core dump handling.

centurion030@james-precisiontower7910:~$

plasmashell --replace &

Results in a brief background and then I am getting the Plasma KDE Crash Handler

centurion030@james-precisiontower7910:~$ kquitapp5 plasmashell && kstart5 plasmashell &

[1] 13755

centurion030@james-precisiontower7910:~$ “Application plasmashell could not be found using service org.kde.plasmashell and path /MainApplication.”

[1]+ Exit 1 kquitapp5 plasmashell && kstart5 plasmashell

centurion030@james-precisiontower7910:~$

nite_route · September 24, 2026, 6:15am

your plasmashell --replace log is dying in the network applet. the useful line is airplaneModeAvailable of null inside org.kde.plasma.networkmanagement. that usually means plasma-nm and the rest of plasma got out of sync after the upgrade, then lock/unlock blows it up.

from the ssh session as your normal user (not root):

sudo apt install --reinstall plasma-nm plasma-desktop plasmashell
rm -rf ~/.cache/plasma* ~/.cache/plasmashell*
systemctl --user restart plasma-plasmashell.service

if it still kcrashes, paste:
journalctl --user -b -u plasma-plasmashell --no-pager | tail -80
and say if that DP-0 + DVI-I-1 dual head setup changed recently.

Centurion030 · September 24, 2026, 11:00am

centurion030@james-precisiontower7910:~$ sudo apt install --reinstall plasma-nm plasma-desktop plasmashell
[sudo] password for centurion030:
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
E: Unable to locate package plasmashell

Centurion030 · September 24, 2026, 11:08am

centurion030@james-precisiontower7910:~$ sudo apt install --reinstall plasma-nm plasma-desktop

centurion030@james-precisiontower7910:~$ rm -rf ~/.cache/plasma* ~/.cache/plasmashell*
centurion030@james-precisiontower7910:~$ systemctl --user restart plasma-plasmashell.service
Job for plasma-plasmashell.service failed because a fatal signal was delivered causing the control process to dump core.
See “systemctl --user status plasma-plasmashell.service” and “journalctl --user -xeu plasma-plasmashell.service” for details.

centurion030@james-precisiontower7910:~$ journalctl --user -b -u plasma-plasmashell --no-pager | tail -80
Sep 24 07:02:16 james-precisiontower7910 systemd[2846]: Starting plasma-plasmashell.service - KDE Plasma Workspace…
Sep 24 07:02:16 james-precisiontower7910 plasmashell[3319]: qt.qpa.xcb: could not connect to display
Sep 24 07:02:16 james-precisiontower7910 plasmashell[3319]: qt.qpa.plugin: Could not load the Qt platform plugin “xcb” in “” even though it was found.
Sep 24 07:02:16 james-precisiontower7910 plasmashell[3319]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Sep 24 07:02:16 james-precisiontower7910 plasmashell[3319]: Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.
Sep 24 07:02:17 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Main process exited, code=dumped, status=6/ABRT
Sep 24 07:02:17 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Failed with result ‘core-dump’.
Sep 24 07:02:17 james-precisiontower7910 systemd[2846]: Failed to start plasma-plasmashell.service - KDE Plasma Workspace.
Sep 24 07:02:17 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Scheduled restart job, restart counter is at 1.
Sep 24 07:02:17 james-precisiontower7910 systemd[2846]: Starting plasma-plasmashell.service - KDE Plasma Workspace…
Sep 24 07:02:17 james-precisiontower7910 plasmashell[3326]: qt.qpa.xcb: could not connect to display
Sep 24 07:02:17 james-precisiontower7910 plasmashell[3326]: qt.qpa.plugin: Could not load the Qt platform plugin “xcb” in “” even though it was found.
Sep 24 07:02:17 james-precisiontower7910 plasmashell[3326]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Sep 24 07:02:17 james-precisiontower7910 plasmashell[3326]: Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.
Sep 24 07:02:18 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Main process exited, code=dumped, status=6/ABRT
Sep 24 07:02:18 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Failed with result ‘core-dump’.
Sep 24 07:02:18 james-precisiontower7910 systemd[2846]: Failed to start plasma-plasmashell.service - KDE Plasma Workspace.
Sep 24 07:02:19 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Scheduled restart job, restart counter is at 2.
Sep 24 07:02:19 james-precisiontower7910 systemd[2846]: Starting plasma-plasmashell.service - KDE Plasma Workspace…
Sep 24 07:02:19 james-precisiontower7910 plasmashell[3333]: qt.qpa.xcb: could not connect to display
Sep 24 07:02:19 james-precisiontower7910 plasmashell[3333]: qt.qpa.plugin: Could not load the Qt platform plugin “xcb” in “” even though it was found.
Sep 24 07:02:19 james-precisiontower7910 plasmashell[3333]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Sep 24 07:02:19 james-precisiontower7910 plasmashell[3333]: Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Main process exited, code=dumped, status=6/ABRT
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Failed with result ‘core-dump’.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: Failed to start plasma-plasmashell.service - KDE Plasma Workspace.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Scheduled restart job, restart counter is at 3.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Start request repeated too quickly.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: plasma-plasmashell.service: Failed with result ‘core-dump’.
Sep 24 07:02:20 james-precisiontower7910 systemd[2846]: Failed to start plasma-plasmashell.service - KDE Plasma Workspace.
centurion030@james-precisiontower7910:~$

DP-0 + DVI-I-1 dual head setup did not change

nite_route · September 24, 2026, 12:22pm

yeah sorry, plasmashell is not its own package on kubuntu. it lives in plasma-workspace.

your log is the real tell though:
Could not load the Qt platform plugin “xcb”

so qt cant talk to x11. from ssh as your user:
sudo apt install --reinstall plasma-workspace plasma-nm plasma-desktop libqt5gui5 libxcb-cursor0 libxcb1
echo $XDG_SESSION_TYPE
echo $DISPLAY
echo $WAYLAND_DISPLAY

if you are on x11 and DISPLAY is empty over ssh, start a local session on the tower or:
export DISPLAY=:0
export XAUTHORITY=/home/centurion030/.Xauthority
systemctl --user restart plasma-plasmashell.service

paste those three env lines plus:
apt-cache policy plasma-workspace | head -5

Centurion030 · September 24, 2026, 12:27pm

Doing.
All konsole windows are gone on the tower when I log in. Funny enough, only kate is open. Okay, following your steps.

Centurion030 · September 24, 2026, 12:32pm

centurion030@james-precisiontower7910:~$ sudo apt install --reinstall plasma-workspace plasma-nm plasma-desktop libqt5gui5 libxcb-cursor0 libxcb1
[sudo] password for centurion030:
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
Note, selecting ‘libqt5gui5t64’ instead of ‘libqt5gui5’
centurion030@james-precisiontower7910:~$ echo $XDG_SESSION_TYPE
tty
centurion030@james-precisiontower7910:~$ echo $DISPLAY

centurion030@james-precisiontower7910:~$ echo $WAYLAND_DISPLAY

centurion030@james-precisiontower7910:~$ export DISPLAY=:0
centurion030@james-precisiontower7910:~$ export XAUTHORITY=/home/centurion030/.Xauthority
centurion030@james-precisiontower7910:~$ systemctl --user restart plasma-plasmashell.service
centurion030@james-precisiontower7910:~$ apt-cache policy plasma-workspace | head -5
plasma-workspace:
Installed: 4:5.27.12-0ubuntu0.1
Candidate: 4:5.27.12-0ubuntu0.1
Version table:
*** 4:5.27.12-0ubuntu0.1 500
centurion030@james-precisiontower7910:~$

Centurion030 · September 24, 2026, 12:33pm

I am ssh’ing into the tower from the laptop. Just to clear up anything. The screen briefly shows up and then goes to black again.

skyfishgoo · September 24, 2026, 2:24pm

show apt list --installed linux-firmware*

Centurion030 · September 24, 2026, 2:33pm

centurion030@james-precisiontower7910:~$ sudo apt list --installed linux-firmware*
[sudo] password for centurion030:
Listing… Done
linux-firmware-amd-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.3 all [installed,automatic]
linux-firmware-amd-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-broadcom-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-marvell-prestera/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-marvell-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-mediatek/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-mellanox-spectrum/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-netronome/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-nvidia-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qlogic/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-realtek/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware/noble-updates,noble-updates,now 20240318.git3b128b60.0ubuntu3.1 all [installed,automatic]
centurion030@james-precisiontower7910:~$

nite_route · September 24, 2026, 2:40pm

yeah XDG_SESSION_TYPE=tty and empty DISPLAY means that restart ran in a pure ssh tty. it will never bring the tower screen back by itself.

on the tower console (ctrl-alt-f3 login) or over ssh after:
sudo systemctl status sddm
sudo journalctl -b -u sddm --no-pager | tail -50
sudo systemctl restart sddm

brief flash then black usually means sddm starts X then the gpu stack falls over. firmware list looks fine so next stop is sddm + the gpu driver.

Centurion030 · September 24, 2026, 2:53pm

Okay. Having to be creative.
● sddm.service - Simple Desktop Display Manager
Loaded: loaded (/usr/lib/systemd/system/sddm.service; enabled; preset: enabled)
Active: active (running) since Thu 2026-09-24 09:57:46 EDT; 48min ago
Docs: man:sddm(1)
man:sddm.conf(5)
Process: 2491 ExecStartPre=/bin/sh -c [ “$(cat /etc/X11/default-display-manager 2>/dev/null)” = “/usr/bin/sddm” ] (code=exited, status=0/SUCCESS)
Main PID: 2523 (sddm)
Tasks: 4 (limit: 309102)
Memory: 194.2M (peak: 195.4M)
CPU: 15.280s
CGroup: /system.slice/sddm.service
├─2523 /usr/bin/sddm
└─2552 /usr/lib/xorg/Xorg -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_dwfEQf -noreset -displayfd 16

Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] returning.
Sep 24 09:58:46 james-precisiontower7910 sddm[2523]: Authentication for user “centurion030” successful
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: pam_unix(sddm:session): session opened for user centurion030(uid=1000) by centurion030(uid=0)
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Auth: sddm-helper exited successfully
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Greeter stopped. SDDM::Auth::HELPER_SUCCESS
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: Writing cookie to “/tmp/xauth_qTQiHC”
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: Starting X11 session: “” “/etc/sddm/Xsession \”/usr/bin/startplasma-x11\“”
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Session started true
Sep 24 09:57:45 james-precisiontower7910 systemd[1]: Starting sddm.service - Simple Desktop Display Manager…
Sep 24 09:57:46 james-precisiontower7910 systemd[1]: Started sddm.service - Simple Desktop Display Manager.
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Initializing…
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Starting…
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Logind interface found
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Adding new display…
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Loaded empty theme configuration
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Xauthority path: “/run/sddm/xauth_dwfEQf”
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Using VT 2
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Display server starting…
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Writing cookie to “/run/sddm/xauth_dwfEQf”
Sep 24 09:57:51 james-precisiontower7910 sddm[2523]: Running: /usr/bin/X -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_dwfEQf -noreset -displayfd
16
Sep 24 09:57:58 james-precisiontower7910 sddm[2523]: Setting default cursor
Sep 24 09:57:58 james-precisiontower7910 sddm[2523]: Running display setup script “/usr/share/sddm/scripts/Xsetup”
Sep 24 09:57:59 james-precisiontower7910 sddm[2523]: Display server started.
Sep 24 09:57:59 james-precisiontower7910 sddm[2523]: Socket server starting…
Sep 24 09:57:59 james-precisiontower7910 sddm[2523]: Socket server started.
Sep 24 09:57:59 james-precisiontower7910 sddm[2523]: Loading theme configuration from “/usr/share/sddm/themes/kubuntu/theme.conf”
Sep 24 09:57:59 james-precisiontower7910 sddm[2523]: Greeter starting…
Sep 24 09:57:59 james-precisiontower7910 sddm-helper[2701]: [PAM] Starting…
Sep 24 09:57:59 james-precisiontower7910 sddm-helper[2701]: [PAM] Authenticating…
Sep 24 09:57:59 james-precisiontower7910 sddm-helper[2701]: [PAM] returning.
Sep 24 09:57:59 james-precisiontower7910 sddm-helper[2701]: pam_unix(sddm-greeter:session): session opened for user sddm(uid=112) by sddm(uid=0)
Sep 24 09:58:01 james-precisiontower7910 sddm[2523]: Greeter session started successfully
Sep 24 09:58:05 james-precisiontower7910 sddm[2523]: Message received from greeter: Connect
Sep 24 09:58:46 james-precisiontower7910 sddm[2523]: Message received from greeter: Login
Sep 24 09:58:46 james-precisiontower7910 sddm[2523]: Reading from “/usr/share/xsessions/plasma.desktop”
Sep 24 09:58:46 james-precisiontower7910 sddm[2523]: Session “/usr/share/xsessions/plasma.desktop” selected, command: “/usr/bin/startplasma-x11” for VT 2
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] Starting…
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] Authenticating…
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] Preparing to converse…
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] Conversation with 1 messages
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: pam_kwallet5(sddm:auth): pam_kwallet5: pam_sm_authenticate
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: [PAM] returning.
Sep 24 09:58:46 james-precisiontower7910 sddm[2523]: Authentication for user “centurion030” successful
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
Sep 24 09:58:46 james-precisiontower7910 sddm-helper[2805]: pam_unix(sddm:session): session opened for user centurion030(uid=1000) by centurion030(uid=0)
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Auth: sddm-helper exited successfully
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Greeter stopped. SDDM::Auth::HELPER_SUCCESS
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: Writing cookie to “/tmp/xauth_qTQiHC”
Sep 24 09:58:47 james-precisiontower7910 sddm-helper[2805]: Starting X11 session: “” “/etc/sddm/Xsession \”/usr/bin/startplasma-x11\“”
Sep 24 09:58:47 james-precisiontower7910 sddm[2523]: Session started true

centurion030@james-precisiontower7910:~$ lspci | grep -iE “vga|3d|nvidia|amd”
03:00.0 VGA compatible controller: NVIDIA Corporation GM107GL [Quadro K2200] (rev a2)
03:00.1 Audio device: NVIDIA Corporation GM107 High Definition Audio Controller [GeForce 940MX] (rev a1)
centurion030@james-precisiontower7910:~$

±----------------------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=========================================================================================|
| 0 N/A N/A 5447 G /usr/lib/xorg/Xorg 244MiB |
| 0 N/A N/A 5571 G /usr/bin/kwalletd5 1MiB |
centurion030@james-precisiontower7910:~$

Centurion030 · September 24, 2026, 2:59pm

even though from the tty:
● sddm.service - Simple Desktop Display Manager
Loaded: loaded (/usr/lib/systemd/system/sddm.service; enabled; preset: enabled)
Active: active (running) since Thu 2026-09-24 10:47:48 EDT; 11min ago
Docs: man:sddm(1)
man:sddm.conf(5)
Process: 5440 ExecStartPre=/bin/sh -c [ “$(cat /etc/X11/default-display-manager 2>/dev/null)” = “/usr/bin/sddm” ] (code=exited, status=0/SUCCESS)
Main PID: 5444 (sddm)
Tasks: 4 (limit: 309102)
Memory: 90.3M (peak: 91.9M)
CPU: 8.469s
CGroup: /system.slice/sddm.service
├─5444 /usr/bin/sddm
└─5447 /usr/lib/xorg/Xorg -nolisten tcp -background none -seat seat0 vt1 -auth /run/sddm/xauth_ykFLaZ -noreset -displayfd 16

Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] returning.
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Authentication for user “centurion030” successful
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_unix(sddm:session): session opened for user centurion030(uid=1000) by centurion030(uid=0)
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: Writing cookie to “/tmp/xauth_OwoGhS”
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: Starting X11 session: “” “/etc/sddm/Xsession \”/usr/bin/startplasma-x11\“”
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Session started true
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Auth: sddm-helper exited successfully
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Greeter stopped. SDDM::Auth::HELPER_SUCCESS
centurion030@james-precisiontower7910:~$

Centurion030 · September 24, 2026, 3:08pm

centurion030@james-precisiontower7910:~$ cat results_for_fix_2.txt
Sep 24 10:47:47 james-precisiontower7910 sddm[2523]: Display server stopped.
Sep 24 10:47:47 james-precisiontower7910 sddm[2523]: Running display stop script (“/usr/share/sddm/scripts/Xstop”)
Sep 24 10:47:47 james-precisiontower7910 systemd[1]: sddm.service: Deactivated successfully.
Sep 24 10:47:47 james-precisiontower7910 systemd[1]: Stopped sddm.service - Simple Desktop Display Manager.
Sep 24 10:47:47 james-precisiontower7910 systemd[1]: sddm.service: Consumed 19.053s CPU time, 195.4M memory peak, 0B memory swap peak.
Sep 24 10:47:48 james-precisiontower7910 systemd[1]: Starting sddm.service - Simple Desktop Display Manager…
Sep 24 10:47:48 james-precisiontower7910 systemd[1]: Started sddm.service - Simple Desktop Display Manager.
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Initializing…
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Starting…
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Logind interface found
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Adding new display…
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Loaded empty theme configuration
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Xauthority path: “/run/sddm/xauth_ykFLaZ”
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Using VT 1
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Display server starting…
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Writing cookie to “/run/sddm/xauth_ykFLaZ”
Sep 24 10:47:48 james-precisiontower7910 sddm[5444]: Running: /usr/bin/X -nolisten tcp -background none -seat seat0 vt1 -auth /run/sddm/xauth_ykFLaZ -noreset -displayfd
16
Sep 24 10:47:50 james-precisiontower7910 sddm[5444]: Setting default cursor
Sep 24 10:47:50 james-precisiontower7910 sddm[5444]: Running display setup script “/usr/share/sddm/scripts/Xsetup”
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Display server started.
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Socket server starting…
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Socket server started.
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Loading theme configuration from “/usr/share/sddm/themes/kubuntu/theme.conf”
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Greeter starting…
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: [PAM] Starting…
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: [PAM] Authenticating…
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: [PAM] returning.
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: pam_unix(sddm-greeter:session): session opened for user sddm(uid=112) by sddm(uid=0)
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: Writing cookie to “/tmp/xauth_LCebNM”
Sep 24 10:47:51 james-precisiontower7910 sddm-helper[5484]: Starting X11 session: “” “/usr/bin/sddm-greeter --socket /tmp/sddm-:0-ctIJaw --theme /usr/share/sddm/themes/k
ubuntu”
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Greeter session started successfully
Sep 24 10:47:51 james-precisiontower7910 sddm[5444]: Message received from greeter: Connect
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Message received from greeter: Login
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Reading from “/usr/share/xsessions/plasma.desktop”
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Session “/usr/share/xsessions/plasma.desktop” selected, command: “/usr/bin/startplasma-x11” for VT 1
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] Starting…
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] Authenticating…
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] Preparing to converse…
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] Conversation with 1 messages
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_kwallet5(sddm:auth): pam_kwallet5: pam_sm_authenticate
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: [PAM] returning.
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Authentication for user “centurion030” successful
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_kwallet5(sddm:setcred): pam_kwallet5: pam_sm_setcred
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_unix(sddm:session): session opened for user centurion030(uid=1000) by centurion030(uid=0)
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: pam_kwallet5(sddm:session): pam_kwallet5: pam_sm_open_session
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: Writing cookie to “/tmp/xauth_OwoGhS”
Sep 24 10:48:04 james-precisiontower7910 sddm-helper[5567]: Starting X11 session: “” “/etc/sddm/Xsession \”/usr/bin/startplasma-x11\“”
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Session started true
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Auth: sddm-helper exited successfully
Sep 24 10:48:04 james-precisiontower7910 sddm[5444]: Greeter stopped. SDDM::Auth::HELPER_SUCCESS

inigmas · September 24, 2026, 3:31pm

my kubuntu 24.04 desktop also stopped working recently. My logs look similar enough to yours; but I’m running an AMD card.

Centurion030 · September 24, 2026, 4:07pm

I have a sinking feeling about this…

inigmas · September 24, 2026, 4:56pm

I tried creating a new test user. When I signed in with them; everything seemed fine. I nuked my `~/.config` directory and now Konsole isn’t even showing up any more. Not sure what else to try.

mak-sim · September 24, 2026, 5:00pm

my ubuntu studio 24.04 desktop is also not working

skyfishgoo · September 24, 2026, 5:04pm

that was why i asked about the linux-firmware package(s) because there was a recent packaging issue that left those with an AMD gpu facing a black screen upon reboot after the update.

the packaging issue has since been corrected and the new firmware suite of packages solves that particular issue, which OP already has installed… so that’s not the source of their problem, but may be related to yours if you don’t have the update applied.

mak-sim · September 24, 2026, 5:09pm

linux-firmware-amd-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.2 all [installed,automatic]
linux-firmware-amd-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-broadcom-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-intel-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-marvell-prestera/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-marvell-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-mediatek/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-mellanox-spectrum/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-netronome/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-nvidia-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qlogic/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-graphics/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-misc/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-qualcomm-wireless/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware-realtek/noble-updates,noble-updates,now 20240318.git3b128b60-0ubuntu3.1 all [installed,automatic]
linux-firmware/noble-updates,noble-updates,now 20240318.git3b128b60.0ubuntu3.1 all [installed,automatic]