Fix issue with automation-playback constantly marking a session dirty.

libs/ardour/ardour/automation_control.h

@@ -152,6 +152,7 @@ class LIBARDOUR_API AutomationControl
 	*/
 	friend class ControlGroup;
 	void set_group (boost::shared_ptr<ControlGroup>);
+	PBD::ScopedConnection _state_changed_connection;
 };
 
 

libs/ardour/automation_control.cc

@@ -60,6 +60,10 @@ AutomationControl::AutomationControl(ARDOUR::Session&                          s
 	if (_desc.toggled) {
 		set_flags (Controllable::Toggle);
 	}
+	boost::shared_ptr<AutomationList> al = alist();
+	if (al) {
+		al->StateChanged.connect_same_thread (_state_changed_connection, boost::bind (&Session::set_dirty, &_session));
+	}
 }
 
 AutomationControl::~AutomationControl ()
@@ -174,7 +178,9 @@ AutomationControl::actually_set_value (double value, PBD::Controllable::GroupCon
 		//<< " (was " << old_value << ") @ " << this << std::endl;
 
 		Changed (true, gcd);
-		_session.set_dirty ();
+		if (!al || !al->automation_playback ()) {
+			_session.set_dirty ();
+		}
 	}
 
 }

libs/ardour/plugin.cc

@@ -450,7 +450,6 @@ void
 Plugin::set_parameter (uint32_t /* which */, float /* value */)
 {
 	_parameter_changed_since_last_preset = true;
-	_session.set_dirty ();
 	PresetDirty (); /* EMIT SIGNAL */
 }