Merge pull request #178195 from dnr/pipewire-systemwide

nixos/pipewire: fix wireplumber with system-wide

nixos/modules/services/desktops/pipewire/wireplumber.nix

···
     environment.systemPackages = [ cfg.package ];
 
     environment.etc."wireplumber/main.lua.d/80-nixos.lua" = lib.mkIf (!pwUsedForAudio) {
-     text = ''
+      text = ''
         -- Pipewire is not used for audio, so prevent it from grabbing audio devices
         alsa_monitor.enable = function() end
       '';
     };
+    environment.etc."wireplumber/main.lua.d/80-systemwide.lua" = lib.mkIf config.services.pipewire.systemWide {
+      text = ''
+        -- When running system-wide, these settings need to be disabled (they
+        -- use functions that aren't available on the system dbus).
+        alsa_monitor.properties["alsa.reserve"] = false
+        default_access.properties["enable-flatpak-portal"] = false
+      '';
+    };
 
     systemd.packages = [ cfg.package ];
 
···
 
     systemd.services.wireplumber.wantedBy = [ "pipewire.service" ];
     systemd.user.services.wireplumber.wantedBy = [ "pipewire.service" ];
+
+    systemd.services.wireplumber.environment = lib.mkIf config.services.pipewire.systemWide {
+      # Force wireplumber to use system dbus.
+      DBUS_SESSION_BUS_ADDRESS = "unix:path=/run/dbus/system_bus_socket";
+    };
   };
 }