Public bug reported:
Release: Ubuntu 26.04 (resolute), MATE desktop
Package: arctica-greeter 0.99.5.0-3ubuntu2, lightdm 1.32.0
Hardware:
- Laptop, internal panel eDP-1 1920x1200, lid open
- Dell dock with two identical monitors via DisplayPort MST
(DP-1-2, DP-1-3, 1920x1080 each)
I produced the attached logs like this:
1. Logrotate
2. Reboot (with dock attached)
3. Wait for error
4. Switch to tty3
5. Logrotate (so *.log.1 contain the failed boot)
6. Reboot
7. Disconnect dock during boot
8. Wait for login dialog to appear
9. Connect Dock
10. Login
11. Copy Log files (so *.log contain the successful boot)
Steps to reproduce:
1. Attach the dock with both external monitors
2. Boot
Expected: login dialog appears.
Actual: all screens stay black with only the mouse cursor. The greeter
process keeps running and never shows a window.
Reproducible every time. Other cases:
- Boot without dock: works.
- Boot without dock, attach dock while the greeter is shown: works,
greeter adapts to the new monitors.
- In the failed state, "systemctl restart lightdm" from a TTY: works,
greeter appears on all monitors.
My interpretation of the Logs:
Both runs show the same GTK CRITICAL assertions around the on-screen
keyboard (gdk_monitor_get_geometry, gtk_window_resize 'width > 0' etc.),
so these appear to be unrelated noise.
The difference: in the successful run, right after these messages:
arctica-greeter.vala:174: settings-daemon plugin xrandr loaded
arctica-greeter.vala:171: xsettings is ready
arctica-greeter.vala:781: Creating background surface
...
arctica-greeter.vala:468: Showing main window
In the failed run none of these lines appear. The greeter seems to wait
indefinitely for mate-settings-daemon's xrandr plugin / xsettings,
which apparently never becomes ready when the MST monitors appear
during settings-daemon startup. With no timeout, the screen stays
black.
This may partly belong to mate-settings-daemon.
I've seed that 0.99.9.4 is in stonking-proposed, but didn't test it
there.
[Claude helped to create this bug report]
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: arctica-greeter 0.99.5.0-3ubuntu2
ProcVersionSignature: Ubuntu 7.0.0-111034.34tux1-tuxedo 7.0.14
Uname: Linux 7.0.0-111034-tuxedo x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: MATE
Date: Sun Oct 11 10:47:26 2026
ProcEnviron:
LANG=de_DE.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm
XDG_RUNTIME_DIR=<set>
SourcePackage: arctica-greeter
UpgradeStatus: Upgraded to resolute on 2026-10-03 (8 days ago)
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2023-04-14T17:12:16.160023
** Affects: arctica-greeter (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute third-party-packages
** Attachment added: "Logs of the boot process"
https://bugs.launchpad.net/bugs/2170479/+attachment/6008141/+files/lightdm-logs.7z
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https://bugs.launchpad.net/bugs/2170479
Title:
Black screens when booting with Dock + 2 monitors
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