Public bug reported: On Ubuntu 26.04 with mutter 50.1, the laptop's built-in 4K panel renders the desktop horizontally compressed when its scale is 200% in the default logical layout mode.
Symptoms - The whole desktop (top bar, wallpaper, windows) is drawn into roughly the left 80% of the panel. - The rightmost ~2–3 inches of the panel are never repainted and keep showing stale content from earlier frames. - Pointer input is offset: clicks register a few inches to the left of the drawn cursor. - It also happens on the GDM greeter. - External monitors on the same session are unaffected. Steps to reproduce 1. Hybrid laptop (Intel iGPU drives the eDP panel and is mutter's primary GPU; NVIDIA dGPU drives four external 1920x1080 monitors). 2. Set the built-in panel (3840x2160) to scale 200% in the default logical layout mode. This is the default after login. 3. Observe the squeezed image and the input offset on the built-in panel. What I tested - Panel at 100% in logical mode: renders correctly. Toggling 200% → 100% clears the squeeze. - Panel at 200% in physical mode (ApplyMonitorsConfig with layout-mode = 2): renders correctly, with input aligned. - Panel mode while squeezed: native [email protected]. This is the only mode the kernel exposes; the other 45 listed by gdctl show --modes are mutter-generated. So it's not a non-native/fallback mode issue. - NVIDIA driver: the symptom was present on 595.99.02 (including at GDM) and persists on 615.71.09. - Kernel logs: no relevant i915 or KMS errors. Expected: the panel renders the full width at scale 2.0 with input aligned, as it does in physical mode. Workaround: re-apply physical layout mode via org.gnome.Mutter.DisplayConfig.ApplyMonitorsConfig after each login. This cannot be made persistent; see the separate bug [link draft 2]. System ┌─────────────┬──────────────────────────────────────────────────────────────────────────────────────┐ │ Component │ Version │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ Release │ Ubuntu 26.04.1 LTS │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ Kernel │ 7.0.0-38-generic │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ mutter │ 50.1-0ubuntu2.4 (libmutter-18-0) │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ gnome-shell │ 50.1-0ubuntu1.3 │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ gdm3 │ 50.1-0ubuntu0.1 │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ Mesa │ 26.0.8-1ubuntu0.3 │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ NVIDIA │ 615.71.09 open (nvidia-driver-615-open), nvidia-drm.modeset=1 │ ├─────────────┼──────────────────────────────────────────────────────────────────────────────────────┤ │ │ Lenovo 20YQ (ThinkPad P1 Gen 4); Intel Tiger Lake-H UHD [8086:9a70] drives eDP-1 │ │ Hardware │ (SDC 0x4157, 3840x2160); NVIDIA RTX A4000 Mobile [10de:24b7] drives DP-4/5/6 and │ │ │ HDMI-1 (1920x1080 each) │ └─────────────┴──────────────────────────────────────────────────────────────────────────────────────┘ Log line: GPU /dev/dri/card2 selected primary from builtin panel presence (card2 = i915) Possibly related: LP #1967450, LP #2162070, upstream mutter #4839 and #4642. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: mutter 50.1-0ubuntu2.4 ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14 Uname: Linux 7.0.0-38-generic x86_64 ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Tue Oct 6 21:57:27 2026 InstallationDate: Installed on 2021-12-28 (1743 days ago) InstallationMedia: Ubuntu 21.10 "Impish Indri" - Release amd64 (20211012) SourcePackage: mutter UpgradeStatus: Upgraded to resolute on 2026-10-05 (1 days ago) ** Affects: mutter (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug resolute wayland-session -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/2169751 Title: Built-in 4K eDP panel renders horizontally squeezed with stale strip and input offset at scale 2.0 in logical layout mode (hybrid Intel/NVIDIA) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2169751/+subscriptions -- desktop-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
