Public bug reported:
Crash Details
Package: gnome-control-center 1:49.0-1ubuntu2 (arm64, Ubuntu 25.10)
Date: Mar 12 17:52:18
Signal: SIGABRT (assertion failure, not a segfault)
Root Cause — from JournalErrors
The crash sequence was:
1. Mode mismatch error: Config not applicable:
GDBus.Error:org.freedesktop.DBus.Error.InvalidArgs: Monitors modes in
logical monitor not equal
GNOME tried to apply a display config where the two monitors had
incompatible display modes (different resolutions/refresh rates). This
is exactly the mirroring problem — to mirror, both outputs need a common
mode, and GNOME couldn't find one between your laptop (1920x1200) and
the external monitor.
2. Fatal assertion: cc-display-panel:ERROR:../panels/display/cc-
display-settings.c:416:cc_display_settings_rebuild_ui: assertion failed:
(modes)
After the mode mismatch, the display settings UI tried to rebuild
itself but the modes list was NULL. The code at cc-display-
settings.c:416 expected a valid modes list and hit g_assert(modes),
which triggered SIGABRT.
3. Minor preceding issue:
on_click_gesture_pressed_cb: assertion 'self->drag_active == FALSE' failed
A drag-state UI glitch also occurred just before the crash.
Summary
This is a bug in gnome-control-center 49.0 on the display panel. When the USB-C
dock connected an external monitor with no compatible common mode for your
laptop's 1920x1200 panel, the settings UI crashed instead of gracefully falling
back. That crash prevented you from ever reaching the mirror/extend toggle.
ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: gnome-control-center 1:49.0-1ubuntu2
ProcVersionSignature: Ubuntu 6.19.0-13.13-qcom-x1e 6.19.5
Uname: Linux 6.19.0-13-qcom-x1e aarch64
ApportVersion: 2.33.1-0ubuntu3
Architecture: arm64
CasperMD5CheckMismatches: ./boot/grub/grub.cfg
CasperMD5CheckResult: fail
CurrentDesktop: ubuntu:GNOME
Date: Fri Mar 13 08:30:12 2026
InstallationDate: Installed on 2026-01-22 (49 days ago)
InstallationMedia: Ubuntu 25.04 "Plucky Puffin" - Release arm64+x1e (20250827)
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/usr/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to questing on 2026-02-03 (38 days ago)
** Affects: gnome-control-center (Ubuntu)
Importance: Undecided
Status: New
** Tags: apport-bug arm64 questing wayland-session
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https://bugs.launchpad.net/bugs/2144077
Title:
mirroring displays that miss-matched resolution failed to drop to
scaled mode - control-center crashes
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