many changes relating to session construction and audioengine interaction

every session member is now initialized using C++ constructor syntax

session construction reordered to clarify the split(s) between work
where the engine is not relevant and work where is it is. this
split is still not 100% obvious, but is enormously clearer than
previously.

if engine/backend are not running as session is created, and the SR
of the sample rate is known, attempt to force backend to that value.

4 files changed, 37 insertions, 14 deletions

diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index d6c6863b14..4992e0a14b 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -268,7 +268,7 @@ ARDOUR_UI::ARDOUR_UI (int *argcp, char **argvp[], const char* localedir)
 
 	/* handle Audio/MIDI setup when session requires it */
 
-	ARDOUR::Session::AudioEngineSetupRequired.connect_same_thread (forever_connections, boost::bind (&ARDOUR_UI::do_audio_midi_setup, this));
+	ARDOUR::Session::AudioEngineSetupRequired.connect_same_thread (forever_connections, boost::bind (&ARDOUR_UI::do_audio_midi_setup, this, _1));
 
 	/* handle sr mismatch with a dialog (PROBLEM: needs to return a value and thus cannot be x-thread) */
 
@@ -4159,10 +4159,12 @@ ARDOUR_UI::launch_audio_midi_setup ()
 }
 						
 int
-ARDOUR_UI::do_audio_midi_setup ()
+ARDOUR_UI::do_audio_midi_setup (uint32_t desired_sample_rate)
 {
 	launch_audio_midi_setup ();
 
+	_audio_midi_setup->set_desired_sample_rate (desired_sample_rate);
+
 	int r = _audio_midi_setup->run ();
 
 	switch (r) {
diff --git a/gtk2_ardour/ardour_ui.h b/gtk2_ardour/ardour_ui.h
index 77e81fd23a..fa8eb18f01 100644
--- a/gtk2_ardour/ardour_ui.h
+++ b/gtk2_ardour/ardour_ui.h
@@ -750,7 +750,7 @@ class ARDOUR_UI : public Gtkmm2ext::UI, public ARDOUR::SessionHandlePtr
 
         EngineControl* _audio_midi_setup;
         void launch_audio_midi_setup ();
-        int do_audio_midi_setup ();
+        int do_audio_midi_setup (uint32_t);
 };
 
 #endif /* __ardour_gui_h__ */
diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index b03dc9a304..b97a7133e6 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -65,6 +65,7 @@ EngineControl::EngineControl ()
 	, control_app_button (_("Launch Control App"))
 	, basic_packer (9, 3)
 	, ignore_changes (0)
+	, _desired_sample_rate (0)
 {
 	build_notebook ();
 
@@ -340,6 +341,8 @@ EngineControl::device_changed ()
 	ignore_changes++;
 
 	/* sample rates */
+	
+	string desired;
 
 	vector<float> sr = backend->available_sample_rates (device_name);
 	for (vector<float>::const_iterator x = sr.begin(); x != sr.end(); ++x) {
@@ -350,11 +353,17 @@ EngineControl::device_changed ()
 			snprintf (buf, sizeof (buf), "%.0f kHz", (*x)/1000.0);
 		}
 		s.push_back (buf);
+		if (*x == _desired_sample_rate) {
+			desired = buf;
+		}
 	}
 
 	set_popdown_strings (sample_rate_combo, s);
-	sample_rate_combo.set_active_text (s.front());
-
+	if (desired.empty()) {
+		sample_rate_combo.set_active_text (s.front());
+	} else {
+		sample_rate_combo.set_active_text (desired);
+	}
 
 	vector<uint32_t> bs = backend->available_buffer_sizes(device_name);
 	s.clear ();
@@ -514,7 +523,9 @@ EngineControl::maybe_display_saved_state ()
 
 	if (state) {
 		ignore_changes++;
-		sample_rate_combo.set_active_text (state->sample_rate);
+		if (!_desired_sample_rate) {
+			sample_rate_combo.set_active_text (state->sample_rate);
+		}
 		buffer_size_combo.set_active_text (state->buffer_size);
 		input_latency.set_value (state->input_latency);
 		output_latency.set_value (state->output_latency);
@@ -843,3 +854,10 @@ EngineControl::manage_control_app_sensitivity ()
 		control_app_button.set_sensitive (true);
 	}
 }
+
+void
+EngineControl::set_desired_sample_rate (uint32_t sr)
+{
+	_desired_sample_rate = sr;
+	device_changed ();
+}
diff --git a/gtk2_ardour/engine_dialog.h b/gtk2_ardour/engine_dialog.h
index cdeb18a2c7..a92d0629f2 100644
--- a/gtk2_ardour/engine_dialog.h
+++ b/gtk2_ardour/engine_dialog.h
@@ -37,14 +37,16 @@
 
 class EngineControl : public ArdourDialog {
   public:
-	EngineControl ();
-	~EngineControl ();
-
-	static bool need_setup ();
-
-	XMLNode& get_state ();
-	void set_state (const XMLNode&);
-
+    EngineControl ();
+    ~EngineControl ();
+    
+    static bool need_setup ();
+    
+    XMLNode& get_state ();
+    void set_state (const XMLNode&);
+    
+    void set_desired_sample_rate (uint32_t);
+    
   private:
     Gtk::Notebook notebook;
 
@@ -153,6 +155,7 @@ class EngineControl : public ArdourDialog {
     void control_app_button_clicked ();
     void manage_control_app_sensitivity ();
     int push_state_to_backend (bool start);
+    uint32_t _desired_sample_rate;
 };
 
 #endif /* __gtk2_ardour_engine_dialog_h__ */