Quick Fix obs-studio 28 crashing Mutter 42

This is a bug in mutter that is fixed in Gnome 43 and will get a fix for Gnome 42 but not likely before we get 43 here.

You can fix it for now on gnome 42 by modifying this pkgbuild

https://aur.archlinux.org/packages/mutter-performance

and adding these 2 MRs (click on the code button and download plain diff)

rename the diffs to mr2636.patch and mr2594.patch and put them in the directory you extracted the pkgbuild to next to the other .patch files.

your .SRCINFO should look like this


pkgbase = mutter-performance
	pkgdesc = A window manager for GNOME | Attempts to improve performances with non-upstreamed merge-requests and frequent stable branch resync
	pkgver = 42.5
	pkgrel = 1
	url = https://gitlab.gnome.org/GNOME/mutter
	arch = x86_64
	license = GPL
	checkdepends = xorg-server-xvfb
	checkdepends = pipewire-session-manager
	checkdepends = python-dbusmock
	makedepends = gobject-introspection
	makedepends = git
	makedepends = egl-wayland
	makedepends = meson
	makedepends = xorg-server
	makedepends = wayland-protocols
	makedepends = sysprof
	makedepends = gi-docgen
	depends = dconf
	depends = gobject-introspection-runtime
	depends = gsettings-desktop-schemas
	depends = libcanberra
	depends = startup-notification
	depends = zenity
	depends = libsm
	depends = gnome-desktop
	depends = libxkbcommon-x11
	depends = gnome-settings-daemon
	depends = libgudev
	depends = libinput
	depends = pipewire
	depends = xorg-xwayland
	depends = graphene
	depends = libxkbfile
	depends = libsysprof-capture
	source = mutter-performance::git+https://gitlab.gnome.org/GNOME/mutter.git#commit=4b35c269c7ad2515f91d2d3ccaea7526e0cb5f97
	source = mr2487.patch
	source = mr2506.patch
	source = mr2636.patch
        source = mr2594.patch
	sha256sums = SKIP
	sha256sums = 1cdd4833e10c1f88311a52df1a34e3ad82641f75e2c1848a9367f2fbc8f8fd29
	sha256sums = d6aa7d5b62b522fe6c448ec0c54826acd9ae19d49389fa26a456e2cdfbdf3294
	sha256sums = SKIP
	sha256sums = SKIP

pkgname = mutter-performance
	groups = gnome
	provides = mutter
	provides = libmutter-10.so
	conflicts = mutter

pkgname = mutter-performance-docs
	pkgdesc = A window manager for GNOME | Attempts to improve performances with non-upstreamed merge-requests and frequent stable branch resync (documentation)
	depends = 
	provides = mutter-docs
	conflicts = mutter-docs

and the pkgbuild should look like this


# Patched package:
# Maintainer: Térence Clastres <t.clastres@gmail.com>
# Co-maintainer: Saren Arterius <saren@wtako.net>
# Co-maintainer: Mingi Sung <FiestaLake@protonmail.com>
# Contributor: Joakim Soderlund <joakim.soderlund@gmail.com>

# Official package:
# Maintainer: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
# Contributor: Ionut Biru <ibiru@archlinux.org>
# Contributor: Michael Kanis <mkanis_at_gmx_dot_de>


### PACKAGE OPTIONS

## MERGE REQUESTS SELECTION
# Merge Requests List: ('579' '2487' '2506')
_merge_requests_to_use=('2487' '2506')

## Disable building a DOCS package
# Remember to unset this variable when producing .SRCINFO
: "${_disable_docs:=""}"


### IMPORTANT: Do no edit below this line unless you know what you're doing

pkgbase=mutter-performance
if [ -n "$_disable_docs" ]; then
  pkgname=mutter-performance
else
  pkgname=(mutter-performance mutter-performance-docs)
fi
pkgver=42.5
pkgrel=1
pkgdesc="A window manager for GNOME | Attempts to improve performances with non-upstreamed merge-requests and frequent stable branch resync"
url="https://gitlab.gnome.org/GNOME/mutter"
arch=(x86_64)
license=(GPL)
depends=(dconf gobject-introspection-runtime gsettings-desktop-schemas
         libcanberra startup-notification zenity libsm gnome-desktop
         libxkbcommon-x11 gnome-settings-daemon libgudev libinput pipewire
         xorg-xwayland graphene libxkbfile libsysprof-capture)
makedepends=(gobject-introspection git egl-wayland meson xorg-server
             wayland-protocols sysprof gi-docgen)
checkdepends=(xorg-server-xvfb pipewire-session-manager python-dbusmock)
_commit=4b35c269c7ad2515f91d2d3ccaea7526e0cb5f97  # tags/42.5^0
source=("$pkgname::git+https://gitlab.gnome.org/GNOME/mutter.git#commit=$_commit"
        'mr2487.patch'
        'mr2506.patch'
        'mr2636.patch'
        'mr2594.patch')
sha256sums=('SKIP'
            '1cdd4833e10c1f88311a52df1a34e3ad82641f75e2c1848a9367f2fbc8f8fd29'
            'd6aa7d5b62b522fe6c448ec0c54826acd9ae19d49389fa26a456e2cdfbdf3294'
            'SKIP'
            'SKIP')

pkgver() {
  cd $pkgname
  git describe --tags | sed 's/[^-]*-g/r&/;s/-/+/g'
}

pick_mr() {
  for mr in "${_merge_requests_to_use[@]}"; do
    if [ "$1" = "$mr" ]; then
      if [ "$2" = "merge" ] || [ -z "$2" ]; then
        echo "Downloading then Merging $1..."
        curl -O "https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/$mr.diff"
        git apply "$mr.diff"
      elif [ "$3" = "revert" ]; then
        echo "Reverting $1..."
        git revert "$2" --no-commit
      elif [ "$3" = "patch" ]; then
	if [ -e ../"$2" ]; then 
          echo "Patching with $2..."
          patch -Np1 -i ../"$2"
        else
          echo "Downloading $mr as $2 then patching..."
          curl -O "https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/$mr.diff" -o "$2"
          patch -Np1 -i "$2"
        fi
      else
        echo "ERROR: wrong argument given: $2"
      fi
      break
    fi
  done
}

prepare() {
  cd $pkgname

  git reset --hard
  git cherry-pick --abort || true

  #git remote add vanvugt https://gitlab.gnome.org/vanvugt/mutter.git || true
  #git remote add verdre https://gitlab.gnome.org/verdre/mutter.git || true
  #git remote add 3v1no https://gitlab.gnome.org/3v1n0/mutter.git || true

  #git fetch vanvugt
  #git fetch verdre
  #git fetch 3v1no


  ### Merge Requests

  # Merge Request Prototype
  # Title:
  # Author:
  # URL:
  # Type:
  # Status:
  # Comment:
  # git cherry-pick -n first_commit^..last_commit
  #
  # Possible Type:
  #   1. Improvement: Makes an already existing feature behave better, more efficiently/reliably.
  #   2. Feature: Adds a new functionality.
  #   3. Fix: Regression/bug fix only available in master (not backported).
  #   4. Cleanup: Code styling improvement, function deprecation, rearrangement...
  #
  # Possible Status:
  #   1. Needs rebase: Conflicts with master branch.
  #   2. Needs review: Mutter maintainers needs to review the new/updated MR and provide feedback.
  #   3. Needs changes: MR needs to be adjusted based on maintainers feedback.
  #   4. Merged: MR approved and it changes commited to master.
  #
  # Generally, a MR status oscillate between 2 and 3 and then becomes 4.


  # Title: backends: Do not reload keymap on new keyboard notifications
  # Author: Carlos Garnacho <carlosg@gnome.org>
  # URL:  https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/579
  # Type: 1
  # Status: 4
  # Comment: Was reverted: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/833
  #          If you use stenography software or play hardcore rhythm games like Lunatic Rave 2/osumania, use it.
  pick_mr '579' ce86f90efbaa51522ba14c5b4cad933c2106de42 'revert'

  # Title: Draft: Dynamic triple/double buffering (v4) for GNOME 42 maintenance
  # Author: Daniel van Vugt <daniel.van.vugt@canonical.com>
  # URL:  https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2487
  # Type: 1
  # Status: 2 & 3
  # Comment: Help GPU frequencies to scale up but not currently working on Wayland.
  #          Derived from !1441 to maintain gnome-42 base support.
  #          Thanks @JockeTF in AUR for the patch backported to gnome-41 base.
  pick_mr '2487' 'mr2487.patch' 'patch'

  # Title: compositor: Use native GL mipmapping instead of MetaTextureTower (v2)
  # Author: Daniel van Vugt <daniel.van.vugt@canonical.com>
  # Author: Neil Moore <dar13.dev@gmail.com>
  # URL: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2506
  # Type: 3
  # Status: 4
  # Comment: Fix #849 (Window previews in the overview are not mipmapped on HiDPI)
  #          (v2) Move the original functionality into its own separate class.
  pick_mr '2506' 'mr2506.patch' 'patch'
  
  patch -Np1 -i $srcdir/mr2636.patch
   
  patch -Np1 -i $srcdir/mr2594.patch

}

build() {
  CFLAGS="${CFLAGS/-O2/-O3} -fno-semantic-interposition"
  LDFLAGS+=" -Wl,-Bsymbolic-functions"

  if [ -n "$_disable_docs" ]; then
    arch-meson $pkgname build \
      -D egl_device=true \
      -D wayland_eglstream=true \
      -D docs=false \
      -D installed_tests=false
  else
    arch-meson $pkgname build \
      -D egl_device=true \
      -D wayland_eglstream=true \
      -D docs=true \
      -D installed_tests=false
  fi

  meson compile -C build
}

_check() (
  mkdir -p -m 700 "${XDG_RUNTIME_DIR:=$PWD/runtime-dir}"
  glib-compile-schemas "${GSETTINGS_SCHEMA_DIR:=$PWD/build/data}"
  export XDG_RUNTIME_DIR GSETTINGS_SCHEMA_DIR
  local _pipewire_session_manager=$(pacman -Qq pipewire-session-manager)

  pipewire &
  _p1=$!

  $_pipewire_session_manager &
  _p2=$!

  trap "kill $_p1 $_p2; wait" EXIT

  meson test -C build --print-errorlogs -t 3
)

check() {
  dbus-run-session xvfb-run -s '-nolisten local +iglx -noreset' \
    bash -c "$(declare -f _check); _check"
}

_pick() {
  local p="$1" f d; shift
  for f; do
    d="$srcdir/$p/${f#$pkgdir/}"
    mkdir -p "$(dirname "$d")"
    mv "$f" "$d"
    rmdir -p --ignore-fail-on-non-empty "$(dirname "$f")"
  done
}

package_mutter-performance() {
  provides=(mutter libmutter-10.so)
  conflicts=(mutter)
  groups=(gnome)

  meson install -C build --destdir "$pkgdir"

  if ! [ -n "$_disable_docs" ]; then
    _pick docs "$pkgdir"/usr/share/mutter-*/doc
  fi
}

if ! [ -n "$_disable_docs" ]; then
  package_mutter-performance-docs() {
    provides=(mutter-docs)
    conflicts=(mutter-docs)
    pkgdesc+=" (documentation)"
    depends=()

    mv docs/* "$pkgdir"
  }
fi

then run makepkg --nocheck -si (the checks part has some issues with pipewire in a running session that are annoying so we skip it)

This will build and install it, you can now use obs 28 on gnome 42 without crashing the session.