[Bug 2169319] Re: amdgpu: screen flashes at 120/144 Hz on RX 9060 XT (gfx1200), regression 7.0.0-34 -> 7.0.0-38

I have the same problem, which started on 7.0.0.38 with Ubuntu 26.04. a RX 9060 XT and a Samsung TV connected in HDMI as monitor, 4k @ 60Hz. The horizontal "bar" so quickly disappears that it's barely visible. It covers like 50%-70% of the screen width, is usually located near the bottom of the screen, and has a height of 10% of the screen height. It's as if a "cloud" of random pixel was appearing in that zone, for a very, very short time. That happens about once or twice per hour, roughly. -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2169319 Title: amdgpu: screen flashes at 120/144 Hz on RX 9060 XT (gfx1200), regression 7.0.0-34 -> 7.0.0-38 Status in linux package in Ubuntu: Confirmed Bug description: After upgrading to linux-image-7.0.0-38-generic, a DisplayPort monitor shows ~1 ms visual flashes (tearing-like) at 120 Hz and 144 Hz. 7.0.0-34-generic is clean at the same refresh rate with identical userspace. Hardware - GPU: AMD Radeon RX 9060 XT (gfx1200), PCI 1002:7590, driver amdgpu - Display: HWV ZQE-CAA, 3440x1440, 165 Hz native, DP-1, 10 bpc, no DSC - Session: GNOME Wayland (mutter 50.1), Mesa 26.0.8 Symptom - Brief flashes on pointer motion and small damage repaints (typing in a terminal, overview hover, mouse movement). GL apps make it more frequent; it still happens with all GPU apps closed. - Clean at 60 Hz and 100 Hz. Glitches at 120 Hz and 144 Hz. - Clean on the GDM greeter. Regression - 7.0.0-34-generic: clean at 144 Hz. 7.0.0-38-generic: glitches at 144 Hz. - Same mutter, Mesa and monitor on both; only the kernel changed. - A second machine (AMD iGPU, internal panel, 7.0.0-34) is unaffected; it has not run -38 yet. Ruled out (still glitches on -38) - Userspace mismatch after upgrade (rebooted after full-upgrade) - GNOME animations disabled - Hardware cursor plane disabled (MUTTER_DEBUG_DISABLE_HW_CURSORS=1, MUTTER_DEBUG_INHIBIT_HW_CURSOR=1, verified in gnome-shell environ) - Overlay planes (MUTTER_DEBUG_FORCE_KMS_MODE=simple, verified) - Link side: dp1 link_settings (4 lanes, 0x1e = HBR3), DSC state (off), max bpc (10), amdgpu_dm_capabilities and amdgpu_dm_dtn_log are identical between -34 and -38 at 144 Hz. No DP link-training/DSC errors in dmesg on either kernel. Suspect commits (from the linux 7.0.0-38.38 changelog, not bisected) 1. drm/amd/display: consolidate DCN vblank/flip handling onto ... 2. drm/amd/display: Fix DTB DTO updates breaking live pixel rate sources 3. drm/amd/display: Fix mem_type change detection for async flips 4. drm/amd/display: Handle struct drm_plane_state.ignore_damage_clips Attached: dp1-link, dm-capabilities and dtn for both kernels, modes-DP1.txt, monitor-edid-34.txt in all in file ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: xorg (not installed) 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: Fri Oct 2 18:38:04 2026 InstallationDate: Installed on 2025-02-22 (587 days ago) InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215) ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/zsh TERM=tmux-256color XDG_RUNTIME_DIR=<set> SourcePackage: xorg Symptom: display UpgradeStatus: Upgraded to resolute on 2026-10-02 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169319/+subscriptions