we need the process lock after all..

diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index e9d85300b7da180492cd87644894810f4f128a9d..aba1c8746050ad136c85f81258c9c604174dcdbd 100644 (file)
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -6719,9 +6719,6 @@ Session::auto_connect (const AutoConnectRequest& ar)
                return;
        }
 
-       //why would we need the process lock ??
-       //Glib::Threads::Mutex::Lock lm (AudioEngine::instance()->process_lock ());
-
        /* If both inputs and outputs are auto-connected to physical ports,
         * use the max of input and output offsets to ensure auto-connected
         * port numbers always match up (e.g. the first audio input and the
@@ -6853,18 +6850,27 @@ void
 Session::auto_connect_thread_run ()
 {
        pthread_set_name (X_("autoconnect"));
-       SessionEvent::create_per_thread_pool (X_("autoconnect"), 256);
-       PBD::notify_event_loops_about_thread_creation (pthread_self(), X_("autoconnect"), 256);
+       SessionEvent::create_per_thread_pool (X_("autoconnect"), 1024);
+       PBD::notify_event_loops_about_thread_creation (pthread_self(), X_("autoconnect"), 1024);
        pthread_mutex_lock (&_auto_connect_mutex);
        while (_ac_thread_active) {
 
-               while (!_auto_connect_queue.empty ()) {
+               if (!_auto_connect_queue.empty ()) {
+                       // Why would we need the process lock ??
+                       // A: if ports are added while we're connecting, the backend's iterator may be invalidated:
+                       //   graph_order_callback() -> resort_routes() -> direct_feeds_according_to_reality () -> backend::connected_to()
+                       //   All ardour-internal backends use a std::vector   xxxAudioBackend::find_port()
+                       //   We have control over those, but what does jack do?
+                       Glib::Threads::Mutex::Lock lm (AudioEngine::instance()->process_lock ());
+
                        Glib::Threads::Mutex::Lock lx (_auto_connect_queue_lock);
-                       if (_auto_connect_queue.empty ()) { break; } // re-check with lock
-                       const AutoConnectRequest ar (_auto_connect_queue.front());
-                       _auto_connect_queue.pop ();
-                       lx.release ();
-                       auto_connect (ar);
+                       while (!_auto_connect_queue.empty ()) {
+                               const AutoConnectRequest ar (_auto_connect_queue.front());
+                               _auto_connect_queue.pop ();
+                               lx.release ();
+                               auto_connect (ar);
+                               lx.acquire ();
+                       }
                }
 
                pthread_cond_wait (&_auto_connect_cond, &_auto_connect_mutex);