Debug mode MUTTER_DEBUG_TRIPLE_BUFFERING=always doesn't work anymore

Bug #2070437 reported by Daniel van Vugt
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
mutter (Ubuntu)
Fix Released
Low
Jeremy Bícha
Noble
Fix Released
Low
Daniel van Vugt
Oracular
Fix Released
Low
Jeremy Bícha

Bug Description

[ Impact ]

Debug mode MUTTER_DEBUG_TRIPLE_BUFFERING=always doesn't result in triple buffering being used anymore.

[ Test Plan ]

1. Add MUTTER_DEBUG_TRIPLE_BUFFERING=always to /etc/environment
2. Reboot.
3. Log into a Wayland session.
4. Open a Terminal window and drag it in circles with the mouse.
5. Verify there is a slight lag between the mouse pointer position and the window position. This means it's always triple buffering (or you accidentally logged into a Xorg session).

[ Where problems could occur ]

Anywhere in frame scheduling, including screen freezes and stutter.

[ Other Info ]

This regression occurred in 46.0 as a result of jbicha and myself working a little too independently. Jeremy identified that the upstream branch supported 46 and cherry-picked that for the Noble release, while I was still working on creating a stable maintenance branch for 46 in https://gitlab.gnome.org/Community/Ubuntu/mutter/-/tree/triple-buffering-v4-46

Fortunately it's very low priority and nobody has actually reported it.

Revision history for this message
Daniel van Vugt (vanvugt) wrote :

According to my upstream notes it could have caused a freeze, but that's not what I am seeing in Noble. Just regular double buffering.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1441#note_2099140

Changed in mutter (Ubuntu Noble):
assignee: nobody → Daniel van Vugt (vanvugt)
milestone: none → ubuntu-24.04.1
importance: Undecided → Low
Changed in mutter (Ubuntu Oracular):
milestone: none → ubuntu-24.10
assignee: nobody → Jeremy Bícha (jbicha)
Changed in mutter (Ubuntu Noble):
status: New → Triaged
description: updated
tags: added: regression-release
Changed in mutter (Ubuntu Noble):
status: Triaged → In Progress
Revision history for this message
Timo Aaltonen (tjaalton) wrote : Please test proposed package

Hello Daniel, or anyone else affected,

Accepted mutter into noble-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/mutter/46.2-1ubuntu0.24.04.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-noble to verification-done-noble. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-noble. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in mutter (Ubuntu Noble):
status: In Progress → Fix Committed
tags: added: verification-needed verification-needed-noble
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

Verified fixed in 46.2-1ubuntu0.24.04.1 using the test plan in the bug description.

tags: added: verification-done-noble
removed: verification-needed-noble
tags: added: verification-done
removed: verification-needed
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package mutter - 46.2-1ubuntu0.24.04.1

---------------
mutter (46.2-1ubuntu0.24.04.1) noble; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 46.2 (LP: #2068598)
    - Fixed mouse clicks falling through to the window behind (LP: #2026194)
    - Fixed a crash in meta_wayland_transaction_commit (LP: #2061739)
    - Fixed night light getting stuck on (LP: #2066902)
  * New upstream release 46.1 (LP: #2064735):
    - Fixed blank screen on hybrid GPU machines using nouveau (LP: #2066931)
    - Fixed a monitor hotplug crash (LP: #2050865)
    - Improved performance on secondary GPU monitors (LP: #2038801)
  * Refreshed patches:
    - Support-Dynamic-triple-double-buffering.patch (LP: #2070437, LP: #2070438)
    - meson-Do-not-mark-CI-test-tools-as-required.patch
    - Mark-several-additional-tests-as-flaky.patch
  * Add clutter/conform gesture tests to the list of known flaky ones:
    it's a new test in Mutter 46 and not yet reliable.
  * Add build-Compile-schemas-locally-for-use-in-build-tests.patch to compile
    gsettings schemas for use in build tests. Debian CI requires this now and
    it makes rebuilds more resilient against infrastructure changes.
  * Add wayland-Disable-linux-drm-syncobj-v1.patch to avoid enabling major
    new features in Noble updates, as detailed in:
    https://lists.ubuntu.com/archives/ubuntu-release/2024-May/006087.html
  * Add backends-Handle-null-views-instead-of-creating-dummy-view.patch
    to prevent "clutter_frame_clock_notify_presented: code should not be
    reached" log spam in some Nvidia Wayland sessions (LP: #1967707)
  * Add backends-Restore-support-for-X11-cursor-themes.patch to restore
    support for X11 cursor themes, which was lost in Mutter 46.0
    (LP: #2062377, LP: #2063869)

  [ Jeremy Bícha ]
  * Stop compiling gsettings schemas in debian/rules
  * Opt into Salsa CI
  * Drop packaging references to Hurd since this is Linux-only
  * Update libmutter-14-0.symbols
  * Update Breaks
  * Refreshed patches:
    - window-Add-ability-to-override-the-edge-constraints.patch
    - x11-Add-support-for-fractional-scaling-using-Randr.patch
  * Drop upstreamed patches:
    - Nvidia-secondary-GPU-copy-acceleration.patch
    - compositor-sync-ring-Allow-the-gpu_fence-to-be-moved.patch

  [ Marco Trevisan ]
  * Add place-Always-center-initial-setup.patch (LP: #2016013)

 -- Daniel van Vugt <email address hidden> Fri, 28 Jun 2024 17:35:12 +0800

Changed in mutter (Ubuntu Noble):
status: Fix Committed → Fix Released
Revision history for this message
Chris Halse Rogers (raof) wrote : Update Released

The verification of the Stable Release Update for mutter has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

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