** Description changed: 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. + 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 24.04, 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
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to 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 -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
