This bug was fixed in the package mutter - 46.2-1ubuntu0.24.04.9
---------------
mutter (46.2-1ubuntu0.24.04.9) noble; urgency=medium
[ Chun-Yi Wu ]
* Backport patches to fix AMD platform Nvidia dGPU screen freeze in
Wayland. It was seen as a screen freeze but actually just running on
the dGPU when that's not wired to the laptop display. (LP: #2111902)
[ Yao Wei (魏銘廷) ]
* d/p/wayland-Pass-latest-cogl-sync_fd-on-kms-update.patch:
Fix issue where glxgears runs slower than display refresh rate
(LP: #2111698)
[ Daniel van Vugt ]
* Add onscreen-native-Return-the-correct-number-of-EGL-modifier.patch
to fix multi-monitor reverse PRIME support on desktops where Nvidia is
primary and an integrated GPU is secondary. (LP: #1978905)
-- Daniel van Vugt <daniel.van.v...@canonical.com> Fri, 30 May 2025
14:17:28 +0800
** Changed in: mutter (Ubuntu Noble)
Status: Fix Committed => Fix Released
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https://bugs.launchpad.net/bugs/2111698
Title:
[SRU] On noble with Intel Arrow Lake systems, glxgears FPS is much
less than the panel refresh rate
Status in OEM Priority Project:
New
Status in mutter package in Ubuntu:
Fix Released
Status in mutter source package in Noble:
Fix Released
Status in mutter source package in Oracular:
Won't Fix
Status in mutter source package in Plucky:
Fix Released
Status in mutter source package in Questing:
Fix Released
Bug description:
[ Impact ]
* When running glxgears fullscreen on Intel Arrow Lake laptop, the
FPS can be dropped to 2/3 of display refresh rate, which should not
happen since glxgears has low workload.
[ Test Plan ]
* Find a laptop with Intel Arrow Lake CPU and use its integrated GPU
* Enter Ubuntu Desktop, ensure nothing else is running, open terminal and run
glxgears -fullscreen
* The FPS of glxgears reported in the terminal should be close to
display refresh rate
* As a regression test, verify that an Intel system *older* than Arrow Lake
achieves
glxgears results close to the display refresh rate.
[ Where problems could occur ]
* This touches the screen refresh part of mutter in Wayland,
therefore if this breaks it could affect all systems using GNOME in
Wayland.
[ Other Info ]
* We don't have other issue reported than glxgears e.g. fullscreen
gaming, however this can be an indicator to actual screen refresh
issues under such config.
=== Original Report ===
[Issue]
Upstream report: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13759
glxgears -fullscreen does not stick to the refresh rate of the display
on Arrow Lake systems.
According to upstream report, applying the following MPs can fix the issue:
* https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3958
* https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3999
I've drafted a debdiff for this issue, but I'd like a review from
whoever knows the internal workings of KMS.
[Reproduce Steps]
Ensure nothing else than terminal is running, then run `glxgears
-fullscreen` on Intel Arrow Lake with integrated GPU
[Expected Behavior]
FPS should be close to the refresh rate of the display.
[Actual Behavior]
From the upstream report (with 75 Hz display):
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
375 frames in 5.0 seconds = 74.992 FPS
286 frames in 5.0 seconds = 57.136 FPS
221 frames in 5.0 seconds = 44.151 FPS
220 frames in 5.0 seconds = 43.953 FPS
216 frames in 5.0 seconds = 43.157 FPS
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