mutter tearing patches

2026-09-03 10:10:52 +02:00
parent 777acf7503
commit c9725d3b78
3 changed files with 103 additions and 1 deletions
@@ -0,0 +1,50 @@
+{ lib, pkgs, ... }:
+
+let
+  # GNOME/mutter!3797, pinned because the MR is still under development.
+  mutterTearingRevision = "a8d56d423edde9e6d76f6b9cab663d82c65cf1a2";
+  mutterTearingPatch = pkgs.fetchurl {
+    url = "https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3797.diff";
+    hash = "sha256-3up5PsHX+BSQRKb9JS5bnJLPaTGmvV55M18tKkepIng=";
+  };
+in
+{
+  nixpkgs.overlays = [
+    (final: prev: {
+      mutter = prev.mutter.overrideAttrs (old: {
+        pname = "mutter-tearing";
+
+        # The MR currently targets Mutter 51. Apply it to the packaged Mutter
+        # 50 source, then resolve the four small context conflicts separately.
+        prePatch = ''
+          ${old.prePatch or ""}
+
+          set +e
+          patch --batch -p1 --forward < ${mutterTearingPatch}
+          mr_status=$?
+          set -e
+
+          if [ "$mr_status" -ne 0 ]; then
+            reject_count="$(find . -name '*.rej' -type f | wc -l)"
+            if [ "$reject_count" -ne 3 ]; then
+              echo "Unexpected number of Mutter !3797 rejects: $reject_count" >&2
+              exit 1
+            fi
+          fi
+
+          patch --batch -p1 --forward < ${./mutter-50-tearing-compat.patch}
+          find . -name '*.rej' -type f -delete
+        '';
+
+        passthru = (old.passthru or { }) // {
+          tearingMr = 3797;
+          tearingRevision = mutterTearingRevision;
+        };
+      });
+    })
+  ];
+
+  # Mutter keeps tearing support behind an experimental runtime switch.
+  environment.sessionVariables.MUTTER_DEBUG_EXPERIMENTAL_FEATURES =
+    lib.mkDefault "tearing";
+}