diff --git a/spa/plugins/support/loop.c b/spa/plugins/support/loop.c
index d17411f91..25637ea82 100644
--- a/spa/plugins/support/loop.c
+++ b/spa/plugins/support/loop.c
@@ -120,6 +120,32 @@ static int loop_remove_source(void *object, struct spa_source *source)
 	return spa_system_pollfd_del(impl->system, impl->poll_fd, source->fd);
 }
 
+static void flush_items(struct impl *impl, bool async)
+{
+	uint32_t index;
+	int res;
+
+	while (spa_ringbuffer_get_read_index(&impl->buffer, &index) > 0) {
+		struct invoke_item *item;
+		bool block;
+
+		item = SPA_MEMBER(impl->buffer_data, index & (DATAS_SIZE - 1), struct invoke_item);
+		block = item->block;
+
+		item->res = item->func ? item->func(&impl->loop,
+				true, item->seq, item->data, item->size,
+			   item->user_data) : 0;
+
+		spa_ringbuffer_read_update(&impl->buffer, index + item->item_size);
+
+		if (block && async) {
+			if ((res = spa_system_eventfd_write(impl->system, impl->ack_fd, 1)) < 0)
+				spa_log_warn(impl->log, NAME " %p: failed to write event fd: %s",
+						impl, spa_strerror(res));
+		}
+	}
+}
+
 static int
 loop_invoke(void *object,
 	    spa_invoke_func_t func,
@@ -135,7 +161,8 @@ loop_invoke(void *object,
 	int res;
 
 	if (in_thread) {
-		res = func(&impl->loop, false, seq, data, size, user_data);
+		flush_items(impl, false);
+		res = func ? func(&impl->loop, false, seq, data, size, user_data) : 0;
 	} else {
 		int32_t filled;
 		uint32_t avail, idx, offset, l0;
@@ -161,6 +188,8 @@ loop_invoke(void *object,
 		item->block = block;
 		item->user_data = user_data;
 
+		spa_log_trace(impl->log, NAME " %p: add item %p filled:%d", impl, item, filled);
+
 		if (l0 > sizeof(struct invoke_item) + size) {
 			item->data = SPA_MEMBER(item, sizeof(struct invoke_item), void);
 			item->item_size = sizeof(struct invoke_item) + size;
@@ -202,28 +231,7 @@ loop_invoke(void *object,
 static void wakeup_func(void *data, uint64_t count)
 {
 	struct impl *impl = data;
-	uint32_t index;
-	int res;
-
-	while (spa_ringbuffer_get_read_index(&impl->buffer, &index) > 0) {
-		struct invoke_item *item;
-		bool block;
-
-		item = SPA_MEMBER(impl->buffer_data, index & (DATAS_SIZE - 1), struct invoke_item);
-		block = item->block;
-
-		item->res = item->func(&impl->loop,
-				true, item->seq, item->data, item->size,
-			   item->user_data);
-
-		spa_ringbuffer_read_update(&impl->buffer, index + item->item_size);
-
-		if (block) {
-			if ((res = spa_system_eventfd_write(impl->system, impl->ack_fd, 1)) < 0)
-				spa_log_warn(impl->log, NAME " %p: failed to write event fd: %s",
-						impl, spa_strerror(res));
-		}
-	}
+	flush_items(impl, true);
 }
 
 static int loop_get_fd(void *object)
@@ -246,11 +254,13 @@ static void loop_enter(void *object)
 {
 	struct impl *impl = object;
 	impl->thread = pthread_self();
+	spa_log_trace(impl->log, NAME" %p: enter %lu", impl, impl->thread);
 }
 
 static void loop_leave(void *object)
 {
 	struct impl *impl = object;
+	spa_log_trace(impl->log, NAME" %p: leave %lu", impl, impl->thread);
 	impl->thread = 0;
 }