6.2 Broken wayland on x1 carbon gen 10 with "a" recent update

Hey all,

/etc/os-release                                                                                      1 ↵
PRETTY_NAME="KDE neon 6.2"
NAME="KDE neon"
VERSION_ID="24.04"
VERSION="6.2"
VERSION_CODENAME=noble
ID=neon
ID_LIKE="ubuntu debian"

I’m seeing something weird since a recent update, been having no issues with sddm->plasma wayland for months… I recently ran a discover update, and noticed something must have happened since some apps were somehow blocking when starting. So I rebooted. SDDM appears, login works, flashes black, brings me back to tty, and back to SDDM. Strange. Repeats again. Tried clearing settings, again.

Then I try in x11 mode and it works. At least that… I can’t figure out what’s happening. This is an intel GPU. No kernel version change, all stock KDE neon 6.2

I do see some issues that could be relevant:

nov. 12 22:16:23 kladenetes kwin_wayland[2082]: kwin_core: Failed to activate /org/freedesktop/login1/session/_35 session. Maybe another compositor is running?
nov. 12 22:16:23 kladenetes kwin_wayland[2082]: kwin_wayland_drm: failed to open drm device at "/dev/dri/card1"
nov. 12 22:16:23 kladenetes kwin_wayland[2082]: kwin_wayland_drm: No suitable DRM devices have been found
[... repeated multiple times just before session closes...]

This error did not happen, before a single “No backend specified, automatically choosing drm” came up.

After that I see pretty much everything going haywire.

Lots of applications coredumping even plasmashell.

nov. 12 22:16:25 kladenetes systemd-coredump[2645]: [🡕] Process 2613 (plasmashell) of user 1000 dumped core.

                                                    Module libgomp.so.1 from deb gcc-14-14.2.0-4ubuntu2~24.04.amd64
                                                    Module libzstd.so.1 from deb libzstd-1.5.5+dfsg2-2build1.1.amd64
                                                    Module libsystemd.so.0 from deb systemd-255.4-1ubuntu8.4.amd64
                                                    Module libudev.so.1 from deb systemd-255.4-1ubuntu8.4.amd64
                                                    Module libgcc_s.so.1 from deb gcc-14-14.2.0-4ubuntu2~24.04.amd64
                                                    Module libstdc++.so.6 from deb gcc-14-14.2.0-4ubuntu2~24.04.amd64
                                                    Stack trace of thread 2613:
                                                    #0  0x00007f5d1da9eb1c __pthread_kill_implementation (libc.so.6 + 0x9eb1c)
                                                    #1  0x00007f5d1da4526e __GI_raise (libc.so.6 + 0x4526e)
                                                    #2  0x00007f5d1da288ff __GI_abort (libc.so.6 + 0x288ff)
                                                    #3  0x00007f5d1e6da02c _Z6qAbortv (libQt6Core.so.6 + 0x4da02c)
                                                    #4  0x00007f5d1e708df8 n/a (libQt6Core.so.6 + 0x508df8)
                                                    #5  0x00007f5d1e70d5b5 _ZNK14QMessageLogger5fatalEPKcz (libQt6Core.so.6 + 0x50d5b5)
                                                    #6  0x00007f5d1eadaa5e n/a (libQt6Gui.so.6 + 0x2daa5e)
                                                    #7  0x00007f5d1ead8350 _ZN22QGuiApplicationPrivate21createEventDispatcherEv (libQt6Gui.so.6 + 0x2d8350)
                                                    #8  0x00007f5d1e6c0449 _ZN23QCoreApplicationPrivate4initEv (libQt6Core.so.6 + 0x4c0449)
                                                    #9  0x00007f5d1ead83ef _ZN22QGuiApplicationPrivate4initEv (libQt6Gui.so.6 + 0x2d83ef)
                                                    #10 0x00007f5d207f62c5 _ZN19QApplicationPrivate4initEv (libQt6Widgets.so.6 + 0x5f62c5)
                                                    #11 0x0000622d2378c38b n/a (plasmashell + 0x3c38b)
                                                    #12 0x00007f5d1da2a1ca __libc_start_call_main (libc.so.6 + 0x2a1ca)
                                                    #13 0x00007f5d1da2a28b __libc_start_main_impl (libc.so.6 + 0x2a28b)
                                                    #14 0x0000622d2378d135 n/a (plasmashell + 0x3d135)

                                                    Stack trace of thread 2639:
                                                    #0  0x00007f5d1db1b4cd __GI___poll (libc.so.6 + 0x11b4cd)
                                                    #1  0x00007f5d1cdaa66e n/a (libglib-2.0.so.0 + 0xbc66e)
                                                    #2  0x00007f5d1cd4aa53 g_main_context_iteration (libglib-2.0.so.0 + 0x5ca53)
                                                    #3  0x00007f5d1e46f4ff _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x26f4ff)
                                                    #4  0x00007f5d1e6c89bb _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x4c89bb)
                                                    #5  0x00007f5d1e5cb7d7 _ZN7QThread4execEv (libQt6Core.so.6 + 0x3cb7d7)
                                                    #6  0x00007f5d1f1d698d n/a (libQt6DBus.so.6 + 0x9b98d)
                                                    #7  0x00007f5d1e585e47 n/a (libQt6Core.so.6 + 0x385e47)
                                                    #8  0x00007f5d1da9ca94 start_thread (libc.so.6 + 0x9ca94)
                                                    #9  0x00007f5d1db29c3c __clone3 (libc.so.6 + 0x129c3c)
                                                    ELF object binary architecture: AMD x86-64

Until eventually:

nov. 12 22:16:26 kladenetes sddm[1254]: Running display stop script  QList("/usr/share/sddm/scripts/Xstop")
nov. 12 22:16:26 kladenetes sddm[1254]: Removing display SDDM::Display(0x60d1a403d100) ...
nov. 12 22:16:26 kladenetes sddm[1254]: Adding new display...
nov. 12 22:16:26 kladenetes sddm[1254]: Loaded empty theme configuration
nov. 12 22:16:26 kladenetes sddm[1254]: Xauthority path: "/run/sddm/xauth_coDoQe"
nov. 12 22:16:26 kladenetes sddm[1254]: Using VT 2
nov. 12 22:16:26 kladenetes sddm[1254]: Display server starting...
nov. 12 22:16:26 kladenetes sddm[1254]: Writing cookie to "/run/sddm/xauth_coDoQe"
nov. 12 22:16:26 kladenetes sddm[1254]: Running: /usr/bin/X -nolisten tcp -background none -seat seat0 vt2 -auth /run/sddm/xauth_coDoQe -noreset -displayfd 18```





Any ideas?

Additional data: it does happen with or without additional monitors(it’s a laptop)

Soooo this is solved. For posteriority: do not trust chrome-remote-desktop if you use wayland. it installs a new dr1 device that breaks kde_wayland.