kms/update: Allow page flip callback listeners on any thread

This hooks into the MetaThread GMainContext callback machinery just
added; and allows receiving page flip callbacks on any thread.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2777>

src/backends/native/meta-kms-impl-device-atomic.c

@@ -755,6 +755,7 @@ process_page_flip_listener (MetaKmsImplDevice  *impl_device,
   meta_kms_page_flip_data_add_listener (page_flip_data,
                                         listener->vtable,
                                         listener->flags,
+                                        listener->main_context,
                                         listener_user_data,
                                         listener_destroy_notify);
 

src/backends/native/meta-kms-impl-device-simple.c

@@ -1091,6 +1091,7 @@ generate_page_flip_datas (MetaKmsImplDevice  *impl_device,
       meta_kms_page_flip_data_add_listener (page_flip_data,
                                             listener->vtable,
                                             listener->flags,
+                                            listener->main_context,
                                             user_data,
                                             destroy_notify);
 
@@ -1113,6 +1114,7 @@ generate_page_flip_datas (MetaKmsImplDevice  *impl_device,
               meta_kms_page_flip_data_add_listener (page_flip_data,
                                                     other_listener->vtable,
                                                     other_listener->flags,
+                                                    other_listener->main_context,
                                                     other_user_data,
                                                     other_destroy_notify);
               listeners = g_list_delete_link (listeners, l);

src/backends/native/meta-kms-impl-device.c

@@ -1064,6 +1064,7 @@ meta_kms_impl_device_process_update (MetaKmsImplDevice *impl_device,
       MetaKms *kms = meta_kms_device_get_kms (priv->device);
 
       meta_kms_queue_callback (kms,
+                               NULL,
                                emit_resources_changed_callback,
                                GUINT_TO_POINTER (changes), NULL);
     }

src/backends/native/meta-kms-page-flip-private.h

@@ -38,6 +38,7 @@ void meta_kms_page_flip_data_unref (MetaKmsPageFlipData *page_flip_data);
 void meta_kms_page_flip_data_add_listener (MetaKmsPageFlipData                 *page_flip_data,
                                            const MetaKmsPageFlipListenerVtable *vtable,
                                            MetaKmsPageFlipListenerFlag          flags,
+                                           GMainContext                        *main_context,
                                            gpointer                             user_data,
                                            GDestroyNotify                       destroy_notify);
 

src/backends/native/meta-kms-page-flip.c

@@ -30,8 +30,11 @@ typedef struct _MetaKmsPageFlipClosure
 {
   const MetaKmsPageFlipListenerVtable *vtable;
   MetaKmsPageFlipListenerFlag flags;
+  GMainContext *main_context;
   gpointer user_data;
   GDestroyNotify destroy_notify;
+
+  MetaKmsPageFlipData *page_flip_data;
 } MetaKmsPageFlipClosure;
 
 struct _MetaKmsPageFlipData
@@ -55,6 +58,7 @@ struct _MetaKmsPageFlipData
 static MetaKmsPageFlipClosure *
 meta_kms_page_flip_closure_new (const MetaKmsPageFlipListenerVtable *vtable,
                                 MetaKmsPageFlipListenerFlag          flags,
+                                GMainContext                        *main_context,
                                 gpointer                             user_data,
                                 GDestroyNotify                       destroy_notify)
 {
@@ -64,6 +68,7 @@ meta_kms_page_flip_closure_new (const MetaKmsPageFlipListenerVtable *vtable,
   *closure = (MetaKmsPageFlipClosure) {
     .vtable = vtable,
     .flags = flags,
+    .main_context = main_context,
     .user_data = user_data,
     .destroy_notify = destroy_notify,
   };
@@ -74,10 +79,20 @@ meta_kms_page_flip_closure_new (const MetaKmsPageFlipListenerVtable *vtable,
 static void
 meta_kms_page_flip_closure_free (MetaKmsPageFlipClosure *closure)
 {
+  g_clear_pointer (&closure->page_flip_data, meta_kms_page_flip_data_unref);
   g_clear_pointer (&closure->user_data, closure->destroy_notify);
   g_free (closure);
 }
 
+static void
+meta_kms_page_closure_set_data (MetaKmsPageFlipClosure *closure,
+                                MetaKmsPageFlipData    *page_flip_data)
+{
+  g_return_if_fail (!closure->page_flip_data);
+
+  closure->page_flip_data = meta_kms_page_flip_data_ref (page_flip_data);
+}
+
 MetaKmsPageFlipData *
 meta_kms_page_flip_data_new (MetaKmsImplDevice *impl_device,
                              MetaKmsCrtc       *crtc)
@@ -118,12 +133,14 @@ void
 meta_kms_page_flip_data_add_listener (MetaKmsPageFlipData                 *page_flip_data,
                                       const MetaKmsPageFlipListenerVtable *vtable,
                                       MetaKmsPageFlipListenerFlag          flags,
+                                      GMainContext                        *main_context,
                                       gpointer                             user_data,
                                       GDestroyNotify                       destroy_notify)
 {
   MetaKmsPageFlipClosure *closure;
 
   closure = meta_kms_page_flip_closure_new (vtable, flags,
+                                            main_context,
                                             user_data,
                                             destroy_notify);
   page_flip_data->closures = g_list_append (page_flip_data->closures, closure);
@@ -142,18 +159,14 @@ meta_kms_page_flip_data_get_crtc (MetaKmsPageFlipData *page_flip_data)
 }
 
 static void
-meta_kms_page_flip_data_flipped (MetaThread *thread,
+invoke_page_flip_closure_flipped (MetaThread *thread,
                                   gpointer    user_data)
 {
-  MetaKmsPageFlipData *page_flip_data = user_data;
+  MetaKmsPageFlipClosure *closure = user_data;
-  GList *l;
+  MetaKmsPageFlipData *page_flip_data = closure->page_flip_data;
 
   meta_assert_not_in_kms_impl (META_KMS (thread));
 
-  for (l = page_flip_data->closures; l; l = l->next)
-    {
-      MetaKmsPageFlipClosure *closure = l->data;
-
   if (page_flip_data->is_symbolic)
     {
       closure->vtable->ready (page_flip_data->crtc,
@@ -168,7 +181,6 @@ meta_kms_page_flip_data_flipped (MetaThread *thread,
                                 closure->user_data);
     }
 }
-}
 
 static MetaKms *
 meta_kms_from_impl_device (MetaKmsImplDevice *impl_device)
@@ -209,64 +221,79 @@ void
 meta_kms_page_flip_data_flipped_in_impl (MetaKmsPageFlipData *page_flip_data)
 {
   MetaKms *kms = meta_kms_from_impl_device (page_flip_data->impl_device);
+  g_autoptr (GList) closures = NULL;
+  GList *l;
 
   meta_assert_in_kms_impl (kms);
 
-  meta_kms_queue_callback (kms,
+  closures = g_steal_pointer (&page_flip_data->closures);
-                           meta_kms_page_flip_data_flipped,
+  for (l = closures; l; l = l->next)
-                           page_flip_data,
-                           (GDestroyNotify) meta_kms_page_flip_data_unref);
-}
-
-static void
-meta_kms_page_flip_data_mode_set_fallback (MetaThread *thread,
-                                           gpointer    user_data)
-{
-  MetaKmsPageFlipData *page_flip_data = user_data;
-  GList *l;
-
-  meta_assert_not_in_kms_impl (META_KMS (thread));
-
-  for (l = page_flip_data->closures; l; l = l->next)
     {
       MetaKmsPageFlipClosure *closure = l->data;
 
+      meta_kms_page_closure_set_data (closure, page_flip_data);
+      meta_kms_queue_callback (kms,
+                               closure->main_context,
+                               invoke_page_flip_closure_flipped,
+                               closure,
+                               (GDestroyNotify) meta_kms_page_flip_closure_free);
+
+    }
+
+  meta_kms_page_flip_data_unref (page_flip_data);
+}
+
+static void
+invoke_page_flip_closure_mode_set_fallback (MetaThread *thread,
+                                            gpointer    user_data)
+{
+  MetaKmsPageFlipClosure *closure = user_data;
+  MetaKmsPageFlipData *page_flip_data = closure->page_flip_data;
+
+  meta_assert_not_in_kms_impl (META_KMS (thread));
+
   closure->vtable->mode_set_fallback (page_flip_data->crtc,
                                       closure->user_data);
 }
-}
 
 void
 meta_kms_page_flip_data_mode_set_fallback_in_impl (MetaKmsPageFlipData *page_flip_data)
 {
   MetaKms *kms = meta_kms_from_impl_device (page_flip_data->impl_device);
+  g_autoptr (GList) closures = NULL;
+  GList *l;
 
   meta_assert_in_kms_impl (kms);
 
+  closures = g_steal_pointer (&page_flip_data->closures);
+  for (l = closures; l; l = l->next)
+    {
+      MetaKmsPageFlipClosure *closure = l->data;
+
+      meta_kms_page_closure_set_data (closure, page_flip_data);
       meta_kms_queue_callback (kms,
-                           meta_kms_page_flip_data_mode_set_fallback,
+                               closure->main_context,
-                           page_flip_data,
+                               invoke_page_flip_closure_mode_set_fallback,
-                           (GDestroyNotify) meta_kms_page_flip_data_unref);
+                               closure,
+                               (GDestroyNotify) meta_kms_page_flip_closure_free);
+    }
+
+  meta_kms_page_flip_data_unref (page_flip_data);
 }
 
 static void
-meta_kms_page_flip_data_discard (MetaThread *thread,
+invoke_page_flip_closure_discarded (MetaThread *thread,
                                     gpointer    user_data)
 {
-  MetaKmsPageFlipData *page_flip_data = user_data;
+  MetaKmsPageFlipClosure *closure = user_data;
-  GList *l;
+  MetaKmsPageFlipData *page_flip_data = closure->page_flip_data;
 
   meta_assert_not_in_kms_impl (META_KMS (thread));
 
-  for (l = page_flip_data->closures; l; l = l->next)
-    {
-      MetaKmsPageFlipClosure *closure = l->data;
-
   closure->vtable->discarded (page_flip_data->crtc,
                               closure->user_data,
                               page_flip_data->error);
 }
-}
 
 void
 meta_kms_page_flip_data_take_error (MetaKmsPageFlipData *page_flip_data,
@@ -282,14 +309,27 @@ meta_kms_page_flip_data_discard_in_impl (MetaKmsPageFlipData *page_flip_data,
                                          const GError        *error)
 {
   MetaKms *kms = meta_kms_from_impl_device (page_flip_data->impl_device);
+  g_autoptr (GList) closures = NULL;
+  GList *l;
 
   meta_assert_in_kms_impl (kms);
 
   if (error)
     meta_kms_page_flip_data_take_error (page_flip_data, g_error_copy (error));
 
+  closures = g_steal_pointer (&page_flip_data->closures);
+  for (l = closures; l; l = l->next)
+    {
+      MetaKmsPageFlipClosure *closure = l->data;
+
+      meta_kms_page_closure_set_data (closure, page_flip_data);
+
       meta_kms_queue_callback (kms,
-                           meta_kms_page_flip_data_discard,
+                               closure->main_context,
-                           page_flip_data,
+                               invoke_page_flip_closure_discarded,
-                           (GDestroyNotify) meta_kms_page_flip_data_unref);
+                               closure,
+                               (GDestroyNotify) meta_kms_page_flip_closure_free);
+    }
+
+  meta_kms_page_flip_data_unref (page_flip_data);
 }

src/backends/native/meta-kms-private.h

@@ -31,6 +31,7 @@ typedef void (* MetaKmsCallback) (MetaKms  *kms,
                                   gpointer  user_data);
 
 void meta_kms_queue_callback (MetaKms            *kms,
+                              GMainContext       *main_context,
                               MetaThreadCallback  callback,
                               gpointer            user_data,
                               GDestroyNotify      user_data_destroy);

src/backends/native/meta-kms-update-private.h

@@ -121,6 +121,7 @@ typedef struct _MetaKmsPageFlipListener
   MetaKmsCrtc *crtc;
   const MetaKmsPageFlipListenerVtable *vtable;
   MetaKmsPageFlipListenerFlag flags;
+  GMainContext *main_context;
   gpointer user_data;
   GDestroyNotify destroy_notify;
 } MetaKmsPageFlipListener;

src/backends/native/meta-kms-update.c

@@ -193,15 +193,36 @@ meta_kms_mode_set_free (MetaKmsModeSet *mode_set)
   g_free (mode_set);
 }
 
+static gboolean
+noop_callback (gpointer user_data)
+{
+  return G_SOURCE_REMOVE;
+}
+
 static void
 meta_kms_page_flip_listener_unref (MetaKmsPageFlipListener *listener)
 {
   if (!g_atomic_ref_count_dec (&listener->ref_count))
     return;
 
+  if (listener->main_context == g_main_context_get_thread_default ())
+    {
       g_clear_pointer (&listener->user_data, listener->destroy_notify);
       g_free (listener);
     }
+  else
+    {
+      GSource *source;
+
+      source = g_idle_source_new ();
+      g_source_set_callback (source, noop_callback,
+                             g_steal_pointer (&listener->user_data),
+                             g_steal_pointer (&listener->destroy_notify));
+      g_source_attach (source, listener->main_context);
+      g_source_unref (source);
+      g_free (listener);
+    }
+}
 
 static gboolean
 drop_plane_assignment (MetaKmsUpdate          *update,
@@ -497,6 +518,7 @@ meta_kms_update_add_page_flip_listener (MetaKmsUpdate                       *upd
                                         MetaKmsCrtc                         *crtc,
                                         const MetaKmsPageFlipListenerVtable *vtable,
                                         MetaKmsPageFlipListenerFlag          flags,
+                                        GMainContext                        *main_context,
                                         gpointer                             user_data,
                                         GDestroyNotify                       destroy_notify)
 {
@@ -510,6 +532,7 @@ meta_kms_update_add_page_flip_listener (MetaKmsUpdate                       *upd
     .crtc = crtc,
     .vtable = vtable,
     .flags = flags,
+    .main_context = main_context,
     .user_data = user_data,
     .destroy_notify = destroy_notify,
   };

src/backends/native/meta-kms-update.h

@@ -168,6 +168,7 @@ void meta_kms_update_add_page_flip_listener (MetaKmsUpdate
                                              MetaKmsCrtc                         *crtc,
                                              const MetaKmsPageFlipListenerVtable *vtable,
                                              MetaKmsPageFlipListenerFlag          flags,
+                                             GMainContext                        *main_context,
                                              gpointer                             user_data,
                                              GDestroyNotify                       destroy_notify);
 

src/backends/native/meta-kms.c

@@ -170,6 +170,7 @@ meta_kms_queue_result_callback (MetaKms               *kms,
                                 MetaKmsResultListener *listener)
 {
   meta_kms_queue_callback  (kms,
+                            NULL,
                             invoke_result_listener,
                             listener,
                             (GDestroyNotify) meta_kms_result_listener_free);
@@ -219,6 +220,7 @@ meta_kms_notify_modes_set (MetaKms *kms)
 
 void
 meta_kms_queue_callback (MetaKms            *kms,
+                         GMainContext       *main_context,
                          MetaThreadCallback  callback,
                          gpointer            user_data,
                          GDestroyNotify      user_data_destroy)
@@ -226,7 +228,7 @@ meta_kms_queue_callback (MetaKms            *kms,
   MetaThread *thread = META_THREAD (kms);
 
   meta_thread_queue_callback (thread,
-                              NULL,
+                              main_context,
                               callback,
                               user_data,
                               user_data_destroy);

src/backends/native/meta-onscreen-native.c

@@ -474,6 +474,7 @@ meta_onscreen_native_flip_crtc (CoglOnscreen                *onscreen,
                                           kms_crtc,
                                           &page_flip_listener_vtable,
                                           flags,
+                                          NULL,
                                           g_object_ref (view),
                                           g_object_unref);
 }
@@ -1548,6 +1549,7 @@ meta_onscreen_native_finish_frame (CoglOnscreen *onscreen,
                                           kms_crtc,
                                           &page_flip_listener_vtable,
                                           META_KMS_PAGE_FLIP_LISTENER_FLAG_NONE,
+                                          NULL,
                                           g_object_ref (onscreen_native->view),
                                           g_object_unref);
   add_onscreen_frame_info (crtc);

src/tests/native-kms-updates.c

@@ -351,6 +351,7 @@ meta_test_kms_update_page_flip (void)
   meta_kms_update_add_page_flip_listener (update, crtc,
                                           &page_flip_listener_vtable,
                                           META_KMS_PAGE_FLIP_LISTENER_FLAG_NONE,
+                                          NULL,
                                           &data,
                                           page_flip_data_destroy);
 
@@ -375,6 +376,7 @@ meta_test_kms_update_page_flip (void)
   meta_kms_update_add_page_flip_listener (update, crtc,
                                           &page_flip_listener_vtable,
                                           META_KMS_PAGE_FLIP_LISTENER_FLAG_NONE,
+                                          NULL,
                                           &data,
                                           page_flip_data_destroy);
 
@@ -594,6 +596,132 @@ meta_test_kms_update_merge (void)
   meta_kms_update_free (update1);
 }
 
+typedef struct _ThreadData
+{
+  GMutex init_mutex;
+  GMainContext *main_context;
+  GMainLoop *main_thread_loop;
+  GThread *thread;
+} ThreadData;
+
+static gpointer
+off_thread_page_flip_thread_func (gpointer user_data)
+{
+  ThreadData *data = user_data;
+  MetaKmsDevice *device;
+  MetaKms *kms;
+  MetaKmsUpdate *update;
+  MetaKmsCrtc *crtc;
+  MetaKmsConnector *connector;
+  MetaKmsMode *mode;
+  g_autoptr (MetaDrmBuffer) primary_buffer1 = NULL;
+  g_autoptr (MetaDrmBuffer) primary_buffer2 = NULL;
+  MetaKmsPlane *primary_plane;
+  PageFlipData page_flip_data = {};
+  MetaKmsFeedback *feedback;
+
+  g_mutex_lock (&data->init_mutex);
+  g_mutex_unlock (&data->init_mutex);
+
+  device = meta_get_test_kms_device (test_context);
+  kms = meta_kms_device_get_kms (device);
+  crtc = meta_get_test_kms_crtc (device);
+  connector = meta_get_test_kms_connector (device);
+  mode = meta_kms_connector_get_preferred_mode (connector);
+
+  meta_thread_register_callback_context (META_THREAD (kms),
+                                         data->main_context);
+
+  update = meta_kms_update_new (device);
+
+  meta_kms_update_mode_set (update, crtc,
+                            g_list_append (NULL, connector),
+                            mode);
+
+  primary_buffer1 = meta_create_test_mode_dumb_buffer (device, mode);
+
+  primary_plane = meta_kms_device_get_primary_plane_for (device, crtc);
+  meta_kms_update_assign_plane (update,
+                                crtc,
+                                primary_plane,
+                                primary_buffer1,
+                                meta_get_mode_fixed_rect_16 (mode),
+                                meta_get_mode_rect (mode),
+                                META_KMS_ASSIGN_PLANE_FLAG_NONE);
+
+  page_flip_data.loop = g_main_loop_new (data->main_context, FALSE);
+  page_flip_data.thread = g_thread_self ();
+  meta_kms_update_add_page_flip_listener (update, crtc,
+                                          &page_flip_listener_vtable,
+                                          META_KMS_PAGE_FLIP_LISTENER_FLAG_NONE,
+                                          data->main_context,
+                                          &page_flip_data,
+                                          page_flip_data_destroy);
+
+  feedback =
+    meta_kms_device_process_update_sync (device, update,
+                                         META_KMS_UPDATE_FLAG_NONE);
+  meta_kms_feedback_unref (feedback);
+
+  g_main_loop_run (page_flip_data.loop);
+  g_assert_cmpint (page_flip_data.state, ==, DESTROYED);
+
+  page_flip_data.state = INIT;
+  update = meta_kms_update_new (device);
+  primary_buffer2 = meta_create_test_mode_dumb_buffer (device, mode);
+  meta_kms_update_assign_plane (update,
+                                crtc,
+                                primary_plane,
+                                primary_buffer2,
+                                meta_get_mode_fixed_rect_16 (mode),
+                                meta_get_mode_rect (mode),
+                                META_KMS_ASSIGN_PLANE_FLAG_NONE);
+  meta_kms_update_add_page_flip_listener (update, crtc,
+                                          &page_flip_listener_vtable,
+                                          META_KMS_PAGE_FLIP_LISTENER_FLAG_NONE,
+                                          data->main_context,
+                                          &page_flip_data,
+                                          page_flip_data_destroy);
+
+  feedback =
+    meta_kms_device_process_update_sync (device, update,
+                                         META_KMS_UPDATE_FLAG_NONE);
+  meta_kms_feedback_unref (feedback);
+
+  g_main_loop_run (page_flip_data.loop);
+  g_assert_cmpint (page_flip_data.state, ==, DESTROYED);
+
+  g_main_loop_unref (page_flip_data.loop);
+
+  g_main_loop_quit (data->main_thread_loop);
+
+  meta_thread_unregister_callback_context (META_THREAD (kms),
+                                           data->main_context);
+
+  return GINT_TO_POINTER (TRUE);
+}
+
+static void
+meta_test_kms_update_off_thread_page_flip (void)
+{
+  ThreadData data = {};
+
+  g_mutex_init (&data.init_mutex);
+  g_mutex_lock (&data.init_mutex);
+  data.main_context = g_main_context_new ();
+  data.main_thread_loop = g_main_loop_new (NULL, FALSE);
+  data.thread = g_thread_new ("Off-thread page flip test",
+                              off_thread_page_flip_thread_func,
+                              &data);
+  g_mutex_unlock (&data.init_mutex);
+
+  g_main_loop_run (data.main_thread_loop);
+  g_assert_cmpint (GPOINTER_TO_INT (g_thread_join (data.thread)), ==, TRUE);
+  g_main_loop_unref (data.main_thread_loop);
+  g_main_context_unref (data.main_context);
+  g_mutex_clear (&data.init_mutex);
+}
+
 static void
 init_tests (void)
 {
@@ -609,6 +737,8 @@ init_tests (void)
                    meta_test_kms_update_page_flip);
   g_test_add_func ("/backends/native/kms/update/merge",
                    meta_test_kms_update_merge);
+  g_test_add_func ("/backends/native/kms/update/off-thread-page-flip",
+                   meta_test_kms_update_off_thread_page_flip);
 }
 
 int