[Bug 2150776] Re: Ubuntu 26.04 GNOME Wayland: random short display/presentation freezes on AMD RX 7900 XT while apps continue running

Same symptom on different hardware — RX 9060 XT (RDNA4) Adding a data point from a different GPU generation, since this doesn't appear to be RX 7900 XT/RDNA3-specific. Hardware: AMD RX 9060 XT / Navi 44 (RDNA4), PCI ID [1002:7590] Kernel: 7.1.2-070102-generic (mainline build, #202606271039 SMP PREEMPT_DYNAMIC, Sat Jun 27 2026) Symptom: Identical "dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us N times" workqueue warnings, recurring across boots. Example from one boot (kernel monotonic timestamps, wall-clock range Jul 11 19:21:52 - Jul 12 00:37:29 — note the count climbs across the boot rather than resetting): [ 370.797119] workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND [ 455.037142] workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us 5 times, consider switching to WQ_UNBOUND [ 4037.810198] workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us 7 times, consider switching to WQ_UNBOUND [ 5131.830194] workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us 11 times, consider switching to WQ_UNBOUND [19307.125552] workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us 19 times, consider switching to WQ_UNBOUND Ruled out via systematic testing (12+ hours real usage under all three conditions simultaneously): 1. VRR/FreeSync — confirmed disabled at both the Xorg driver level (VariableRefresh: disabled) and the KWin compositor level (vrrPolicy: Never on both outputs). Warning still fired. 2. DPM/mclk power-state switching — GPU pinned to power_dpm_force_performance_level=high for the entire session (static top pstate, no automatic transitions). Warning still fired. 3. Refresh rate/modeset switching — both monitors static at 3440x1440@60Hz for the whole boot, no modeset or hotplug events in kernel or Xorg logs. Warning still fired. Since all three of the obvious triggers were independently ruled out, this points toward the underlying mechanism rather than any of the usual suspects (adaptive sync, power states, or display timing changes). Looked into the driver code and found dm_handle_vmin_vmax_update is a workqueue handler introduced specifically to offload dc_stream_adjust_vmin_vmax() off the interrupt handler so it can wait on dc_lock instead of racing it (see the amd-gfx patch thread on "fix dmub access race condition"): https://www.mail-archive.com/amd-gfx@lists.freedesktop.org/msg126413.html So the warning itself looks like the race-condition fix's own offload mechanism hitting contention, rather than being triggered by any user-facing setting. Happy to provide full journalctl -k output or test a debug kernel build if that'd help narrow it down further. -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2150776 Title: Ubuntu 26.04 GNOME Wayland: random short display/presentation freezes on AMD RX 7900 XT while apps continue running Status in linux package in Ubuntu: Confirmed Bug description: After installing Ubuntu 26.04 LTS, the display randomly freezes for a short time, usually a few hundred milliseconds to around one second. This is most visible in games and video playback, but it can also happen outside games (e.g. watching a video or just using Ubuntu). During the freeze, the application/game continues running. For example, in Counter-Strike 2 or Albion Online, if I am moving when the freeze happens, after the screen updates again my character is farther ahead. This suggests the system/game/input are still running, but the display/presentation stops updating temporarily. Audio usually continues normally. Very rarely, during longer freezes, audio repeats/stutters briefly. This did not happen on the same hardware with Ubuntu 24.04.4, Ubuntu 25.04, or Ubuntu 25.10. It started only on Ubuntu 26.04. Hardware: - CPU: AMD Ryzen 7 7700X - GPU: AMD Radeon RX 7900 XT / Navi 31 - Motherboard: ASRock B650M Pro RS WiFi - RAM: 32 GB - Monitors: 2x Dell S2721HS, 1920x1080, 60/74.97 Hz Software: - Ubuntu 26.04 LTS - GNOME Shell 50.1 - Wayland session - Mutter/libmutter 50.1 - Kernel 7.0.0-15-generic - Mesa 26.0.3 - RADV/radeonsi - Xwayland 24.1.10 What I tried: - Disabled VRR: no change - Tested 60 Hz and 74.97 Hz: no useful change - Disabled second monitor: no change - Disabled all GNOME Shell extensions: no change - Created a clean new user account and tested there: still freezes - Disabled Ryzen iGPU so only RX 7900 XT remained visible: still freezes - Updated motherboard BIOS from 1.30 to 4.20: no change - Tried amdgpu.dcdebugmask=0x12, 0x20012, 0x20052: no change - Tried runtime power_dpm_force_performance_level=high: no change - Tried MUTTER_DEBUG_FORCE_KMS_MODE=simple, MUTTER_DEBUG_KMS_THREAD_TYPE=user, MUTTER_DEBUG_DISABLE_HW_CURSORS=1: no change - Tried disabling unredirect/direct scanout through GNOME Looking Glass: no change - Kernel logs do not show amdgpu ring timeout or GPU reset during freezes - dmesg did show repeated AMD display-manager workqueue warnings: "dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us" Expected: The display should continue presenting frames smoothly. Actual: The visible display freezes briefly, then jumps forward, while the application continues running underneath. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: libmutter-18-0 50.1-0ubuntu2 ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0 Uname: Linux 7.0.0-15-generic x86_64 ApportVersion: 2.34.0-0ubuntu2 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Thu Apr 30 21:47:54 2026 InstallationDate: Installed on 2026-04-29 (1 days ago) InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1) SourcePackage: mutter UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2150776/+subscriptions