Your message dated Sat, 02 May 2026 15:39:20 +0200
with message-id <[email protected]>
and subject line Re: Bug#1112243: lightdm: plasma wayland session not starting,
returning to login screen
has caused the Debian Bug report #1112243,
regarding lightdm: plasma wayland session not starting, returning to login
screen
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
1112243: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1112243
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: lightdm
Version: 1.32.0-6+b2
Severity: important
Dear Maintainer,
Starting a plasma wayland session from lightdm fails and returns to the lightdm
login screen.
A respective error message can be found in the user's .xsession-errors log:
---------- .xsession-errors ----------
Xsession: X session started for masch at Wed Aug 27 07:41:07 PM CEST 2025
dbus-update-activation-environment: setting
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=KDE
Xsession: unable to launch
"/usr/lib/x86_64-linux-gnu/libexec/plasma-dbus-run-session-if-needed
/usr/bin/startplasma-wayland" X session ---
"/usr/lib/x86_64-linux-gnu/libexec/plasma-dbus-run-session-if-needed
/usr/bin/startplasma-wayland" not found; falling back to default session.
xrdb: Can't open display ''
xhost: unable to open display ""
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
$DISPLAY is not set or cannot connect to the X server.
--------------------------------------------------------------------------------
The error message can be traced back to
/etc/X11/Xsession.d/20x11-common_process-args.
It is triggered by the
"session-wrapper=/etc/X11/Xsession"
setting in /usr/share/lightdm/lightdm.conf.d/01_debian.conf which is
not compatible with the
"Exec=/usr/lib/x86_64-linux-gnu/libexec/plasma-dbus-run-session-if-needed
/usr/bin/startplasma-wayland"
setting in /usr/share/wayland-sessions/plasma.desktop.
Reason is that the Xsession wrapper is not able to handle commands
with arguments. The 20x11-common_process-args script that is sourced
by Xsession fails at
'if command -v "$1" >/dev/null; then....'
because arguments are considered part of the cmd (note the double
quotes around $1) which cannot be found. This is related to bugs
#694832, #566825 #694832, #566825 which are raised against x11-common
and go partly back to 2010. While this issue could be resolved in the
x11-common package, alternative solutions can be considered in the
context of plasma-workspace or lightdm packages.
Possible solution that work for me are:
1) x11-common: Remove the double quotes in 20x11-common_process-args
surrounding $1 argument.
I consider this only a workaround as this may break cases where
whitespaces are part of the cmd. But then, who would use whitespaces
in filenames of system executables?
or
2) plasma-workspace: Remove the dbus wrapper call
(plasma-dbus-run-session-if-needed) in
/usr/share/wayland-sessions/plasma.desktop.
Apparently, in my system that wrapper call is not needed. It also
seems not to be used when starting plasma-wayland from sddm but there
may well be a reason why it was introduced. Alternatively, it could be
wrapped in yet another wrapper script without arguments (not really
elegant).
or
3) lightdm: Replace the session wrapper call in
/usr/share/lightdm/lightdm.conf.d/01_debian.conf.
[preferred solution]
An alternative wrapper that actually works for me is the one shipped
with sddm (/etc/sddm/wayland-session), but I would avoid to add a
dependency on sddm and rather prefer a separate version shipped with
lightdm. Alternatively a common wayland wrapper could be created that
would be shared across display managers (would require further
reconciliation across maintainers).
N.b. Actually, using an X11 wrapper script for a wayland session appears
strange. By using a wayland specific wrapper logs could also end up in
a wayland specific log file (instead of .xsession-errors).
Further relevant packages are
- x11-common 1:7.7+24
(/etc/X11/Xsession.d/20x11-common_process-args)
- plasma-workspace 4:6.3.6-2 (/usr/share/wayland-sessions/plasma.desktop)
*** End of the template - remove these template lines ***
-- System Information:
Debian Release: 13.0
APT prefers stable-updates
APT policy: (990, 'stable-updates'), (990, 'stable-security'), (990, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 6.15.6-aragorn (SMP w/12 CPU threads; PREEMPT)
Locale: LANG=C, LC_CTYPE=de_DE.utf-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages lightdm depends on:
ii adduser 3.152
ii dbus 1.16.2-2
ii debconf [debconf-2.0] 1.5.91
ii libaudit1 1:4.0.2-2+b2
ii libc6 2.41-12
ii libgcrypt20 1.11.0-7
ii libglib2.0-0t64 2.84.3-1
ii libpam-systemd [logind] 257.7-1
ii libpam0g 1.7.0-5
ii libxcb1 1.17.0-2+b1
ii libxdmcp6 1:1.1.5-1
ii lightdm-gtk-greeter [lightdm-greeter] 2.0.9-1
Versions of packages lightdm recommends:
ii xserver-xorg 1:7.7+24
Versions of packages lightdm suggests:
ii accountsservice 23.13.9-7
ii upower 1.90.9-1
pn xserver-xephyr <none>
-- Configuration Files:
/etc/lightdm/lightdm.conf changed [not included]
/etc/lightdm/users.conf changed [not included]
/etc/pam.d/lightdm changed [not included]
-- debconf information:
lightdm/daemon_name: /usr/sbin/lightdm
* shared/default-x-display-manager: lightdm
--- End Message ---
--- Begin Message ---
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
On Sat, 2026-05-02 at 14:37 +0200, [email protected] wrote:
> For trixie and forky the issue has been resolved with the update of x11-
> common to 1:7.7+24+deb13u1 / 1:7.7+25.
Marking as fixed then, although best would be to reassign and mark with x11-
common fixed version.
Regards,
- --
Yves-Alexis
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