** Description changed: After updating from Kubuntu 25.10 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) Addition: if I disconnect the external monitor from the dock, I can boot and use the system normally (but of course with only one screen). All this worked without issue on Ubuntu 25.10, although I don't know the exact driver versions anymore. I therefore consider this a regression. Current setup: - Lenovo laptop Legion 7 16IRX9 (MT_83FD_BU_idea_FM_Legion 7 16IRX9) - CPU Intel(R) Core(TM) i9-14900HX - Nvidia Geforce RTX 4060 mobile - Wayland - Kubuntu 26.04 LTS - Nvidia driver 595.71.05 - USB Docking station: Club3D CSV-1585 - External monitor HP e243i 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 GpuHangFrequency: Continuously GpuHangReproducibility: Yes, I can easily reproduce it GpuHangStarted: Immediately after installing this version of Ubuntu + + Update: I now also tried to disconnect the USB dock and connect the external monitor through the HDMI port of the laptop. This also triggers the issue, so it seems not to be caused by the dock. + I also noticed that during the system freeze: + - The external monitor still displays the last image that was on the screen, as long as the system remains powered. + - A crash kernel seems to start. However, it does not boot, or it crashes with a purple screen saying: + KERNEL PANIC! + Please reboot your computer. + Fatal exception in interrupt
-- You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to plasma-workspace in Ubuntu. https://bugs.launchpad.net/bugs/2154647 Title: External screen makes system crash To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plasma-workspace/+bug/2154647/+subscriptions -- kubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs
