From 0d050de94e3ae5a1a0dc36114df1995b042f3b80 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 9 Jul 2016 17:42:58 +0200
Subject: [PATCH] move latency-recompute into dedicated thread.

this fixes an issue with jack1 and jack_latency_recompute() since must not
send a server request from inside the server callback.
---
 libs/ardour/ardour/route.h   |  1 +
 libs/ardour/ardour/session.h |  2 ++
 libs/ardour/plugin_insert.cc |  4 +---
 libs/ardour/session.cc       | 16 ++++++++++++++++
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index 9d16c00ba3..bef1a54569 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -360,6 +360,7 @@ public:
 	/** the processors have changed; the parameter indicates what changed */
 	PBD::Signal1<void,RouteProcessorChange> processors_changed;
 	PBD::Signal1<void,void*> record_enable_changed;
+	PBD::Signal0<void> processor_latency_changed;
 	/** the metering point has changed */
 	PBD::Signal0<void>       meter_change;
 	PBD::Signal0<void>       signal_latency_changed;
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index ebafdd82f6..82c9231cfb 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1509,8 +1509,10 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	typedef std::queue<AutoConnectRequest> AutoConnectQueue;
 	Glib::Threads::Mutex  _auto_connect_queue_lock;
 	AutoConnectQueue _auto_connect_queue;
+	guint _latency_recompute_pending;
 
 	void auto_connect (const AutoConnectRequest&);
+	void queue_latency_recompute ();
 
 	/* SessionEventManager interface */
 
diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 4bbeed5cf1..0beb4c2fdb 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -2959,10 +2959,8 @@ PluginInsert::latency_changed ()
 {
 	// this is called in RT context, LatencyChanged is emitted after run()
 	_latency_changed = true;
-#if 1 // TODO check possible deadlock in RT-context (esp. with jack) latency-callback.
 	// XXX This also needs a proper API not an owner() hack.
-	static_cast<Route*>(owner ())->processors_changed (RouteProcessorChange ()); /* EMIT SIGNAL */
-#endif
+	static_cast<Route*>(owner ())->processor_latency_changed (); /* EMIT SIGNAL */
 }
 
 void
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index bf8291e4b0..74f20306d2 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -279,6 +279,7 @@ Session::Session (AudioEngine &eng,
 	, _reconnecting_routes_in_progress (false)
 	, _route_deletion_in_progress (false)
 	, destructive_index (0)
+	, _latency_recompute_pending (0)
 	, _track_number_decimals(1)
 	, default_fade_steepness (0)
 	, default_fade_msecs (0)
@@ -3418,6 +3419,7 @@ Session::add_routes_inner (RouteList& new_routes, bool input_auto_connect, bool
 
 		r->output()->changed.connect_same_thread (*this, boost::bind (&Session::set_worst_io_latencies_x, this, _1, _2));
 		r->processors_changed.connect_same_thread (*this, boost::bind (&Session::route_processors_changed, this, _1));
+		r->processor_latency_changed.connect_same_thread (*this, boost::bind (&Session::queue_latency_recompute, this));
 
 		if (r->is_master()) {
 			_master_out = r;
@@ -6838,6 +6840,16 @@ Session::auto_connect_route (boost::shared_ptr<Route> route, bool connect_inputs
 	}
 }
 
+void
+Session::queue_latency_recompute ()
+{
+	g_atomic_int_inc (&_latency_recompute_pending);
+	if (pthread_mutex_trylock (&_auto_connect_mutex) == 0) {
+		pthread_cond_signal (&_auto_connect_cond);
+		pthread_mutex_unlock (&_auto_connect_mutex);
+	}
+}
+
 void
 Session::auto_connect (const AutoConnectRequest& ar)
 {
@@ -7003,6 +7015,10 @@ Session::auto_connect_thread_run ()
 			}
 		}
 
+		while (g_atomic_int_and (&_latency_recompute_pending, 0)) {
+			update_latency_compensation ();
+		}
+
 		pthread_cond_wait (&_auto_connect_cond, &_auto_connect_mutex);
 	}
 	pthread_mutex_unlock (&_auto_connect_mutex);