Public bug reported:
After updating from Kubuntu 24.04 to 26.04 my system no longer works correctly.
I've narrowed it down to use my external screen. I'm using a Lenove laptop, for
which the external screen is connected through an external USB dock.
When the system starts, and external dock is connected, the system hangs hard.
ctr-alt-sysrq busier does not work. I have to press power button for several
seconds to switch off the system
If I do not connect external dock during boot, the system starts normally. I
can connect the dock after logging in to the Wayland Kubuntu session, and still
use it. But once I move my mouse cursor from the internal (laptop) screen to
the external screen, the system hangs hard (again magic sysrq not working)
All this worked without issue on Ubuntu 24.04, although I don't know the exact
driver versions anymore.
Current setup:
- Lenovo laptop
- CPU Intel(R) Core(TM) i9-14900HX
- Nvidia Geforce RTX 4060 mobile
- Wayland
- Kubuntu 26.04 LTS
- Nvidia driver 595.71.05
Based on some googling I tried nvidia driver 580, adding nvidia-
drm.modeset=0/1 as boot parameter, and I tried X11 session. Only the X11
session worked properly, but there I cannot scale the monitors properly
(one has a 3200 pixel width, while the other has 1920)
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: plasma-session-wayland 4:6.6.4-0ubuntu2
ProcVersionSignature: Ubuntu 7.0.0-22.22-generic 7.0.0
Uname: Linux 7.0.0-22-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia zfs
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: KDE
Date: Sat May 30 20:32:36 2026
InstallationDate: Installed on 2024-11-16 (560 days ago)
InstallationMedia: Ubuntu 24.10 "Oracular Oriole" - Release amd64 (20241009.4)
SourcePackage: plasma-workspace
UpgradeStatus: Upgraded to resolute on 2026-05-28 (2 days ago)
modified.conffile..etc.logrotate.d.apport: [modified]
mtime.conffile..etc.logrotate.d.apport: 2024-12-12T16:20:53.613902
** Affects: ubuntu
Importance: Undecided
Status: New
** Tags: amd64 apport-bug nvidia regression resolute wayland
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https://bugs.launchpad.net/bugs/2154647
Title:
External screen makes system crash
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