Public bug reported:

[ 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.

** Affects: mutter (Ubuntu)
     Importance: Low
     Assignee: Jeremy Bícha (jbicha)
         Status: Fix Released

** Affects: mutter (Ubuntu Noble)
     Importance: Low
     Assignee: Daniel van Vugt (vanvugt)
         Status: Triaged

** Affects: mutter (Ubuntu Oracular)
     Importance: Low
     Assignee: Jeremy Bícha (jbicha)
         Status: Fix Released


** Tags: noble oracular regression-release triple-buffering

** Also affects: mutter (Ubuntu Noble)
   Importance: Undecided
       Status: New

** Also affects: mutter (Ubuntu Oracular)
   Importance: Low
       Status: Fix Released

** Changed in: mutter (Ubuntu Noble)
     Assignee: (unassigned) => Daniel van Vugt (vanvugt)

** Changed in: mutter (Ubuntu Noble)
    Milestone: None => ubuntu-24.04.1

** Changed in: mutter (Ubuntu Noble)
   Importance: Undecided => Low

** Changed in: mutter (Ubuntu Oracular)
    Milestone: None => ubuntu-24.10

** Changed in: mutter (Ubuntu Oracular)
     Assignee: (unassigned) => Jeremy Bícha (jbicha)

** Changed in: mutter (Ubuntu Noble)
       Status: New => Triaged

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https://bugs.launchpad.net/bugs/2070437

Title:
  Debug mode MUTTER_DEBUG_TRIPLE_BUFFERING=always doesn't work anymore

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