[mutter] backends/native: Ignore udev events while we're paused

[Marge Bot <marge-bot src gnome org>]

commit cbfb59b828dbd095b27d44e88fc77ac024fdea74
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Mon Mar 22 17:44:11 2021 +0100

    backends/native: Ignore udev events while we're paused
    
    When the native backend is paused we still process the udev events
    even though this isn't needed and may just cause unneeded events to be
    triggered afterwards.
    
    Since we'll resume with full changes on such event, we can just block
    the signal hander when paused and restore it afterwards.
    
    As per this we can cleanup also a bit the device adding signal handling
    given that now we don't have to disconnect/reconnect it again.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1964>

 src/backends/native/meta-backend-native.c | 35 +++++--------------------------
 src/backends/native/meta-udev.c           | 12 +++++++++++
 src/backends/native/meta-udev.h           |  4 ++++
 3 files changed, 21 insertions(+), 30 deletions(-)
---
diff --git a/src/backends/native/meta-backend-native.c b/src/backends/native/meta-backend-native.c
index 81d9629d05..2cc9add75d 100644
--- a/src/backends/native/meta-backend-native.c
+++ b/src/backends/native/meta-backend-native.c
@@ -87,8 +87,6 @@ struct _MetaBackendNative
   MetaKms *kms;
 
   gboolean is_headless;
-
-  gulong udev_device_added_handler_id;
 };
 
 static GInitableIface *initable_parent_iface;
@@ -100,20 +98,11 @@ G_DEFINE_TYPE_WITH_CODE (MetaBackendNative, meta_backend_native, META_TYPE_BACKE
                          G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,
                                                 initable_iface_init))
 
-static void
-disconnect_udev_device_added_handler (MetaBackendNative *native);
-
 static void
 meta_backend_native_dispose (GObject *object)
 {
   MetaBackendNative *native = META_BACKEND_NATIVE (object);
 
-  if (native->udev_device_added_handler_id)
-    {
-      disconnect_udev_device_added_handler (native);
-      native->udev_device_added_handler_id = 0;
-    }
-
   if (native->kms)
     meta_kms_prepare_shutdown (native->kms);
 
@@ -485,20 +474,6 @@ on_udev_device_added (MetaUdev          *udev,
   meta_backend_add_gpu (backend, META_GPU (new_gpu_kms));
 }
 
-static void
-connect_udev_device_added_handler (MetaBackendNative *native)
-{
-  native->udev_device_added_handler_id =
-    g_signal_connect (native->udev, "device-added",
-                      G_CALLBACK (on_udev_device_added), native);
-}
-
-static void
-disconnect_udev_device_added_handler (MetaBackendNative *native)
-{
-  g_clear_signal_handler (&native->udev_device_added_handler_id, native->udev);
-}
-
 static gboolean
 init_gpus (MetaBackendNative  *native,
            GError            **error)
@@ -549,7 +524,9 @@ init_gpus (MetaBackendNative  *native,
       return FALSE;
     }
 
-  connect_udev_device_added_handler (native);
+  g_signal_connect_object (native->udev, "device-added",
+                           G_CALLBACK (on_udev_device_added), native,
+                           0);
 
   return TRUE;
 }
@@ -724,8 +701,7 @@ meta_backend_native_pause (MetaBackendNative *native)
 
   meta_seat_native_release_devices (seat);
   meta_renderer_pause (renderer);
-
-  disconnect_udev_device_added_handler (native);
+  meta_udev_pause (native->udev);
 
   meta_monitor_manager_native_pause (monitor_manager_native);
 }
@@ -749,10 +725,9 @@ void meta_backend_native_resume (MetaBackendNative *native)
                            "Backend (resume)");
 
   meta_monitor_manager_native_resume (monitor_manager_native);
+  meta_udev_resume (native->udev);
   meta_kms_resume (native->kms);
 
-  connect_udev_device_added_handler (native);
-
   meta_seat_native_reclaim_devices (seat);
   meta_renderer_resume (renderer);
 
diff --git a/src/backends/native/meta-udev.c b/src/backends/native/meta-udev.c
index c0e0e165fd..16c44dc138 100644
--- a/src/backends/native/meta-udev.c
+++ b/src/backends/native/meta-udev.c
@@ -222,6 +222,18 @@ meta_udev_new (MetaBackendNative *backend_native)
   return udev;
 }
 
+void
+meta_udev_pause (MetaUdev *udev)
+{
+  g_signal_handler_block (udev->gudev_client, udev->uevent_handler_id);
+}
+
+void
+meta_udev_resume (MetaUdev *udev)
+{
+  g_signal_handler_unblock (udev->gudev_client, udev->uevent_handler_id);
+}
+
 static void
 meta_udev_finalize (GObject *object)
 {
diff --git a/src/backends/native/meta-udev.h b/src/backends/native/meta-udev.h
index 7b179329eb..4d85c8f041 100644
--- a/src/backends/native/meta-udev.h
+++ b/src/backends/native/meta-udev.h
@@ -44,6 +44,10 @@ gboolean meta_udev_is_drm_device (MetaUdev    *udev,
 GList * meta_udev_list_drm_devices (MetaUdev  *udev,
                                     GError   **error);
 
+void meta_udev_pause (MetaUdev *udev);
+
+void meta_udev_resume (MetaUdev *udev);
+
 MetaUdev * meta_udev_new (MetaBackendNative *backend_native);
 
 #endif /* META_UDEV_H */