cursor patch

systems/x86_64-linux/drivebystation-nix/mutter-50-tearing-compat.patch

@@ -1,18 +1,3 @@
-diff --git a/src/compositor/meta-compositor-view-native.c b/src/compositor/meta-compositor-view-native.c
---- a/src/compositor/meta-compositor-view-native.c
-+++ b/src/compositor/meta-compositor-view-native.c
-@@ -289,9 +289,11 @@ find_scanout_candidate (MetaCompositorView  *compositor_view,
-     return FALSE;
- 
-   if (!meta_stage_view_is_cursor_overlay_inhibited (view) &&
-+      !meta_onscreen_native_is_tearing_enabled (
-+        META_ONSCREEN_NATIVE (framebuffer)) &&
-       surface_actor_has_overlapping_cursor_overlays (compositor,
-                                                      compositor_view,
-                                                      surface_actor))
-     {
-       meta_topic (META_DEBUG_RENDER,
-                   "No direct scanout candidate: overlapping software cursors");
 diff --git a/src/meson.build b/src/meson.build
 --- a/src/meson.build
 +++ b/src/meson.build

systems/x86_64-linux/drivebystation-nix/mutter-tearing.nix

@@ -14,6 +14,10 @@ in
       mutter = prev.mutter.overrideAttrs (old: {
         pname = "mutter-tearing";
 
+        # nixpkgs leaves Mutter's verbose topics compiled out by default.
+        # This is required for MUTTER_DEBUG=kms to emit the async commit flags.
+        mesonFlags = (old.mesonFlags or [ ]) ++ [ "-Dverbose=true" ];
+
         # The MR currently targets Mutter 51. Apply it to the packaged Mutter
         # 50 source, then resolve the four small context conflicts separately.
         prePatch = ''
@@ -44,7 +48,12 @@ in
     })
   ];
 
+  environment.sessionVariables = {
     # Mutter keeps tearing support behind an experimental runtime switch.
-  environment.sessionVariables.MUTTER_DEBUG_EXPERIMENTAL_FEATURES =
-    lib.mkDefault "tearing";
+    MUTTER_DEBUG_EXPERIMENTAL_FEATURES = lib.mkDefault "tearing";
+
+    # Temporarily expose whether async atomic commits reach KMS or fall back
+    # to synchronized presentation. Remove this after collecting the log.
+    MUTTER_DEBUG = lib.mkDefault "kms";
+  };
 }