Public bug reported: Ubuntu 26.04.1 LTS shows severely washed-out / low-contrast colors when HDR is enabled on an external HDR monitor connected to an AMD Radeon 680M system.
System: Ubuntu 26.04.1 LTS GNOME Shell 50.1-0ubuntu1.3 GPU: AMD Radeon 680M (Rembrandt) Kernel driver: amdgpu Mesa: 26.0.8-1ubuntu0.3 Kernel: 7.0.0-34-generic Monitor: Dell S2721DGF Resolution: 2560x1440 Session type: Wayland Steps to reproduce: Open Settings -> Displays. Enable HDR for the external Dell S2721DGF monitor. Observe the desktop and SDR content. Expected result: SDR desktop content should retain normal black levels, contrast and colors while HDR is enabled, with HDR content using the appropriate extended luminance range. Actual result: The entire image becomes significantly washed out when HDR is enabled. Blacks appear raised and overall contrast is reduced. Disabling HDR immediately restores normal colors. Additional information: The same Dell S2721DGF monitor does not exhibit this problem when HDR is enabled from another Ubuntu machine equipped with an NVIDIA RTX 2060. On the affected machine: OpenGL vendor string: AMD OpenGL renderer string: AMD Radeon 680M (radeonsi, rembrandt, ACO, DRM 3.64, 7.0.0-34-generic) OpenGL version string: 4.6 (Compatibility Profile) Mesa 26.0.8-1ubuntu0.3 gdctl show detects the monitor as: Monitor DP-2 (Dell Inc. 27") Product: DELL S2721DGF Current mode: [email protected] There is no SDR content brightness / reference luminance adjustment exposed in GNOME Settings on this system. Because the same monitor behaves correctly on the RTX 2060 system, this appears to be specific to the AMD/Mutter HDR output or color-management path rather than the monitor itself. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: gnome-shell 50.1-0ubuntu1.3 ProcVersionSignature: Ubuntu 7.0.0-34.34-generic 7.0.14 Uname: Linux 7.0.0-34-generic x86_64 ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Thu Oct 1 14:28:02 2026 DisplayManager: gdm3 InstallationDate: Installed on 2024-09-12 (749 days ago) InstallationMedia: Ubuntu 24.04 LTS "Noble Numbat" - Release amd64 (20240424) ProcEnviron: LANG=ja_JP.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> RelatedPackageVersions: mutter-common 50.1-0ubuntu2.4 SourcePackage: gnome-shell UpgradeStatus: Upgraded to resolute on 2026-10-01 (0 days ago) ** Affects: gnome-shell (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug resolute wayland-session -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2169105 Title: HDR output is washed out on AMD Radeon 680M while NVIDIA works correctly To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2169105/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
