[mutter/gnome-3-36] backends/x11: Emit CLUTTER_DEVICE_ADDED events for initial devices

[Carlos Garnacho <carlosg src gnome org>]

commit 1f16a134414747ac378fb5085a99d1ccc8e7a4e2
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Nov 6 18:00:55 2020 +0100

    backends/x11: Emit CLUTTER_DEVICE_ADDED events for initial devices
    
    This is similar to commit b9e5a2d6e23, but for the X11 backend.
    
    Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1466
    Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1495
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1553
    
    (cherry-picked from commit b6211bb6842fd7f88bc4f70f0d268614b85f4b3d)

 src/backends/x11/meta-backend-x11.c |  7 +++++++
 src/backends/x11/meta-seat-x11.c    | 19 +++++++++++++++++++
 src/backends/x11/meta-seat-x11.h    |  2 ++
 3 files changed, 28 insertions(+)
---
diff --git a/src/backends/x11/meta-backend-x11.c b/src/backends/x11/meta-backend-x11.c
index 7bb8ff3d1e..e18e6a1ab9 100644
--- a/src/backends/x11/meta-backend-x11.c
+++ b/src/backends/x11/meta-backend-x11.c
@@ -524,6 +524,8 @@ meta_backend_x11_post_init (MetaBackend *backend)
   MetaBackendX11 *x11 = META_BACKEND_X11 (backend);
   MetaBackendX11Private *priv = meta_backend_x11_get_instance_private (x11);
   MetaMonitorManager *monitor_manager;
+  ClutterBackend *clutter_backend;
+  ClutterSeat *seat;
   int major, minor;
   gboolean has_xi = FALSE;
 
@@ -576,6 +578,11 @@ meta_backend_x11_post_init (MetaBackend *backend)
   priv->touch_replay_sync_atom = XInternAtom (priv->xdisplay,
                                               "_MUTTER_TOUCH_SEQUENCE_SYNC",
                                               False);
+
+  clutter_backend = meta_backend_get_clutter_backend (backend);
+  seat = clutter_backend_get_default_seat (clutter_backend);
+  meta_seat_x11_notify_devices (META_SEAT_X11 (seat),
+                                CLUTTER_STAGE (meta_backend_get_stage (backend)));
 }
 
 static ClutterBackend *
diff --git a/src/backends/x11/meta-seat-x11.c b/src/backends/x11/meta-seat-x11.c
index 6f0db3a7f7..491b82fae7 100644
--- a/src/backends/x11/meta-seat-x11.c
+++ b/src/backends/x11/meta-seat-x11.c
@@ -1383,6 +1383,25 @@ meta_seat_x11_get_property (GObject    *object,
     }
 }
 
+void
+meta_seat_x11_notify_devices (MetaSeatX11  *seat_x11,
+                             ClutterStage *stage)
+{
+  GHashTableIter iter;
+  ClutterInputDevice *device;
+
+  g_hash_table_iter_init (&iter, seat_x11->devices_by_id);
+  while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &device))
+    {
+      ClutterEvent *event;
+
+      event = clutter_event_new (CLUTTER_DEVICE_ADDED);
+      clutter_event_set_device (event, device);
+      clutter_event_set_stage (event, stage);
+      clutter_do_event (event);
+    }
+}
+
 static void
 meta_seat_x11_constructed (GObject *object)
 {
diff --git a/src/backends/x11/meta-seat-x11.h b/src/backends/x11/meta-seat-x11.h
index d27ec5fa9d..9240258026 100644
--- a/src/backends/x11/meta-seat-x11.h
+++ b/src/backends/x11/meta-seat-x11.h
@@ -36,6 +36,8 @@ ClutterInputDevice * meta_seat_x11_lookup_device_id (MetaSeatX11 *seat_x11,
                                                      int          device_id);
 void meta_seat_x11_select_stage_events (MetaSeatX11  *seat,
                                         ClutterStage *stage);
+void meta_seat_x11_notify_devices (MetaSeatX11  *seat_x11,
+                                   ClutterStage *stage);
 
 G_END_DECLS