lots of changes to auto-start (and stop) the backend for latency measurements, and continuing work on the session construction/engine configuration flow

gtk2_ardour/ardour_ui.cc

@@ -384,25 +384,8 @@ ARDOUR_UI::create_global_port_matrix (ARDOUR::DataType type)
 void
 ARDOUR_UI::attach_to_engine ()
 {
-	AudioEngine::instance()->Stopped.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_stopped, this), gui_context());
 	AudioEngine::instance()->Running.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_running, this), gui_context());
-	AudioEngine::instance()->SampleRateChanged.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::update_sample_rate, this, _1), gui_context());
-
-	AudioEngine::instance()->Halted.connect_same_thread (halt_connection, boost::bind (&ARDOUR_UI::engine_halted, this, _1, false));
-
 	ARDOUR::Port::set_connecting_blocked (ARDOUR_COMMAND_LINE::no_connect_ports);
-
-	/* if there is only one audio/midi backend, and it does not require setup, get our use of it underway
-	 * right here (we need to know the client name and potential session ID
-	 * to do this, which is why this is here, rather than in, say,
-	 * ARDOUR::init().
-	 */
-
-	if (!AudioEngine::instance()->setup_required()) {
-		const AudioBackendInfo* backend = AudioEngine::instance()->available_backends().front();
-		AudioEngine::instance()->set_backend (backend->name, ARDOUR_COMMAND_LINE::backend_client_name, ARDOUR_COMMAND_LINE::backend_session_uuid);
-		AudioEngine::instance()->start ();
-	}
 }
 
 void
@@ -524,6 +507,12 @@ ARDOUR_UI::post_engine ()
 	 */
 
 	ARDOUR::init_post_engine ();
+	
+	/* connect to important signals */
+
+	AudioEngine::instance()->Stopped.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::engine_stopped, this), gui_context());
+	AudioEngine::instance()->SampleRateChanged.connect (forever_connections, MISSING_INVALIDATOR, boost::bind (&ARDOUR_UI::update_sample_rate, this, _1), gui_context());
+	AudioEngine::instance()->Halted.connect_same_thread (halt_connection, boost::bind (&ARDOUR_UI::engine_halted, this, _1, false));
 
 	_tooltips.enable();
 
@@ -4161,6 +4150,8 @@ ARDOUR_UI::launch_audio_midi_setup ()
 int
 ARDOUR_UI::do_audio_midi_setup (uint32_t desired_sample_rate)
 {
+	cerr << "DO-AMS\n";
+
 	launch_audio_midi_setup ();
 
 	_audio_midi_setup->set_desired_sample_rate (desired_sample_rate);

gtk2_ardour/engine_dialog.cc

@@ -29,6 +29,7 @@
 
 #include "pbd/error.h"
 #include "pbd/xml++.h"
+#include "pbd/unwind.h"
 
 #include <gtkmm/stock.h>
 #include <gtkmm/notebook.h>
@@ -95,15 +96,6 @@ EngineControl::EngineControl ()
 	if (audio_setup) {
 		set_state (*audio_setup);
 	} 
-
-	ARDOUR::AudioEngine::instance()->Stopped.connect (*this, MISSING_INVALIDATOR, boost::bind (&EngineControl::disable_latency_tab, this), gui_context());
-
-	if (!ARDOUR::AudioEngine::instance()->connected()) {
-		ARDOUR::AudioEngine::instance()->Running.connect (*this, MISSING_INVALIDATOR, boost::bind (&EngineControl::enable_latency_tab, this), gui_context());
-		disable_latency_tab ();
-	} else {
-		enable_latency_tab ();
-	}
 }
 
 void
@@ -281,9 +273,18 @@ and microphone.\n\n\
 	driver_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::driver_changed));
 	sample_rate_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::sample_rate_changed));
 	buffer_size_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::buffer_size_changed));
+	device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+
+	input_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	output_latency.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	input_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+	output_channels.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::parameter_changed));
+
+
 	input_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &input_channels));
 	output_channels.signal_output().connect (sigc::bind (sigc::ptr_fun (&EngineControl::print_channel_count), &output_channels));
-	device_combo.signal_changed().connect (sigc::mem_fun (*this, &EngineControl::device_changed));
+
+	notebook.signal_switch_page().connect (sigc::mem_fun (*this, &EngineControl::on_switch_page));
 }
 
 EngineControl::~EngineControl ()
@@ -297,6 +298,8 @@ EngineControl::disable_latency_tab ()
 	vector<string> empty;
 	set_popdown_strings (lm_output_channel_combo, empty);
 	set_popdown_strings (lm_input_channel_combo, empty);
+	lm_measure_button.set_sensitive (false);
+	lm_use_button.set_sensitive (false);
 }
 
 void
@@ -311,6 +314,9 @@ EngineControl::enable_latency_tab ()
 	ARDOUR::AudioEngine::instance()->get_physical_inputs (ARDOUR::DataType::AUDIO, inputs);
 	set_popdown_strings (lm_input_channel_combo, inputs);
 	lm_input_channel_combo.set_active_text (inputs.front());
+
+	lm_measure_button.set_sensitive (true);
+	lm_use_button.set_sensitive (true);
 }
 
 void
@@ -384,10 +390,26 @@ EngineControl::list_devices ()
 	set_popdown_strings (device_combo, available_devices);
 	
 	if (!available_devices.empty()) {
+		sample_rate_combo.set_sensitive (true);
+		buffer_size_combo.set_sensitive (true);
+		input_latency.set_sensitive (true);
+		output_latency.set_sensitive (true);
+		input_channels.set_sensitive (true);
+		output_channels.set_sensitive (true);
+						
+		/* changing the text in the combo will trigger device_changed()
+		   which should populate the parameter controls
+		*/
+		
 		device_combo.set_active_text (available_devices.front());
+	} else {
+		sample_rate_combo.set_sensitive (true);
+		buffer_size_combo.set_sensitive (true);
+		input_latency.set_sensitive (true);
+		output_latency.set_sensitive (true);
+		input_channels.set_sensitive (true);
+		output_channels.set_sensitive (true);
 	}
-
-	device_changed ();
 }
 	
 void
@@ -468,7 +490,13 @@ EngineControl::device_changed ()
 
 	ignore_changes--;
 
+	/* pick up any saved state for this device */
+
 	maybe_display_saved_state ();
+
+	/* and push it to the backend */
+
+	push_state_to_backend (false);
 }	
 
 void 
@@ -483,6 +511,7 @@ EngineControl::sample_rate_changed ()
 	*/
 
 	show_buffer_duration ();
+	push_state_to_backend (false);
 	save_state ();
 
 }
@@ -495,6 +524,7 @@ EngineControl::buffer_size_changed ()
 	}
 
 	show_buffer_duration ();
+	push_state_to_backend (false);
 	save_state ();
 }
 
@@ -522,6 +552,14 @@ EngineControl::show_buffer_duration ()
 	buffer_size_duration_label.set_text (buf);
 }
 
+void
+EngineControl::parameter_changed ()
+{
+	if (!ignore_changes) {
+		save_state ();
+	}
+}
+
 EngineControl::State*
 EngineControl::get_matching_state (const string& backend,
 				   const string& driver,
@@ -927,23 +965,47 @@ EngineControl::set_desired_sample_rate (uint32_t sr)
 	device_changed ();
 }
 
-/* latency measurement */
-
 void
-EngineControl::update_latency_display ()
+EngineControl::on_switch_page (GtkNotebookPage*, guint page_num)
 {
-	ARDOUR::framecnt_t const sample_rate = ARDOUR::AudioEngine::instance()->sample_rate();
+	if (page_num == 2) {
-        if (sample_rate == 0) {
+		/* latency tab */
-                lm_results.set_text (_("Disconnected from audio engine"));
+
-        } else {
+		if (!ARDOUR::AudioEngine::instance()->running()) {
-                char buf[64];
+			
-                //snprintf (buf, sizeof (buf), "%10.3lf frames %10.3lf ms",
+			PBD::Unwinder<uint32_t> protect_ignore_changes (ignore_changes, ignore_changes + 1);
-		//(float)_pi->latency(), (float)_pi->latency() * 1000.0f/sample_rate);
+			
-		strcpy (buf, "got something");
+			/* save any existing latency values */
-                lm_results.set_text(buf);
+			
-        }
+			uint32_t il = (uint32_t) input_latency.get_value ();
+			uint32_t ol = (uint32_t) input_latency.get_value ();
+
+			/* reset to zero so that our new test instance of JACK
+			   will be clean of any existing latency measures.
+			*/
+			
+			input_latency.set_value (0);
+			output_latency.set_value (0);
+			
+			push_state_to_backend (false);
+
+			/* reset control */
+
+			input_latency.set_value (il);
+			output_latency.set_value (ol);
+		}
+
+		if (ARDOUR::AudioEngine::instance()->prepare_for_latency_measurement()) {
+			disable_latency_tab ();
+		}
+		enable_latency_tab ();
+	} else {
+		ARDOUR::AudioEngine::instance()->stop_latency_detection();
+	}
 }
 
+/* latency measurement */
+
 bool
 EngineControl::check_latency_measurement ()
 {
@@ -975,6 +1037,7 @@ EngineControl::check_latency_measurement ()
         }
 
 	uint32_t frames_total = mtdm->del();
+	cerr << "total = " << frames_total << " delay = " << ARDOUR::AudioEngine::instance()->latency_signal_delay() << endl;
 	uint32_t extra = frames_total - ARDOUR::AudioEngine::instance()->latency_signal_delay();
 
         snprintf (buf, sizeof (buf), "%u samples %10.3lf ms", extra, extra * 1000.0f/sample_rate);
@@ -992,7 +1055,6 @@ EngineControl::check_latency_measurement ()
         }
 
         if (solid) {
-                // _pi->set_measured_latency (rint (mtdm->del()));
                 lm_measure_button.set_active (false);
 		lm_use_button.set_sensitive (true);
                 strcat (buf, " (set)");
@@ -1010,7 +1072,6 @@ EngineControl::latency_button_toggled ()
 
 		ARDOUR::AudioEngine::instance()->set_latency_input_port (lm_input_channel_combo.get_active_text());
 		ARDOUR::AudioEngine::instance()->set_latency_output_port (lm_output_channel_combo.get_active_text());
-		cerr << "latency detection on " << lm_input_channel_combo.get_active_text() << " => " << lm_output_channel_combo.get_active_text() << endl;
 		ARDOUR::AudioEngine::instance()->start_latency_detection ();
                 lm_results.set_text (_("Detecting ..."));
                 latency_timeout = Glib::signal_timeout().connect (mem_fun (*this, &EngineControl::check_latency_measurement), 250);
@@ -1018,7 +1079,6 @@ EngineControl::latency_button_toggled ()
         } else {
 		ARDOUR::AudioEngine::instance()->stop_latency_detection ();
                 latency_timeout.disconnect ();
-                update_latency_display ();
         }
 }
 

gtk2_ardour/engine_dialog.h

@@ -118,6 +118,7 @@ class EngineControl : public ArdourDialog, public PBD::ScopedConnectionList {
     void backend_changed ();
     void sample_rate_changed ();
     void buffer_size_changed ();
+    void parameter_changed ();
 
     uint32_t get_rate() const;
     uint32_t get_buffer_size() const;
@@ -172,10 +173,11 @@ class EngineControl : public ArdourDialog, public PBD::ScopedConnectionList {
     /* latency measurement */
     void latency_button_toggled ();
     bool check_latency_measurement ();
-    void update_latency_display ();
     sigc::connection latency_timeout;
     void enable_latency_tab ();
     void disable_latency_tab ();
+
+    void on_switch_page (GtkNotebookPage*, guint page_num);
 };
 
 #endif /* __gtk2_ardour_engine_dialog_h__ */

libs/ardour/ardour/audioengine.h

@@ -188,6 +188,7 @@ public:
     /* latency measurement */
 
     MTDM* mtdm();
+    int  prepare_for_latency_measurement ();
     void start_latency_detection ();
     void stop_latency_detection ();
     void set_latency_input_port (const std::string&);
@@ -225,6 +226,7 @@ public:
     std::string               _latency_input_name;
     std::string               _latency_output_name;
     framecnt_t                _latency_signal_latency;
+    bool                      _started_for_latency;
 
     void meter_thread ();
     void start_metering_thread ();

libs/ardour/audioengine.cc

@@ -80,6 +80,7 @@ AudioEngine::AudioEngine ()
 	, _latency_output_port (0)
 	, _latency_flush_frames (0)
 	, _latency_signal_latency (0)
+	, _started_for_latency (false)
 {
 	g_atomic_int_set (&m_meter_exit, 0);
 	discover_backends ();
@@ -202,6 +203,13 @@ AudioEngine::process_callback (pframes_t nframes)
 	bool return_after_remove_check = false;
 
 	if (_measuring_latency && _mtdm) {
+		/* run a normal cycle from the perspective of the PortManager
+		   so that we get silence on all registered ports.
+		   
+		   we overwrite the silence on the two ports used for latency
+		   measurement.
+		*/
+		
 		PortManager::cycle_start (nframes);
 		PortManager::silence (nframes);
 
@@ -609,7 +617,9 @@ AudioEngine::start ()
 	
 	start_metering_thread ();
 	
-	Running(); /* EMIT SIGNAL */
+	if (!_started_for_latency) {
+		Running(); /* EMIT SIGNAL */
+	}
 	
 	return 0;
 }
@@ -632,6 +642,7 @@ AudioEngine::stop ()
 	_measuring_latency = false;
 	_latency_output_port = 0;
 	_latency_input_port = 0;
+	_started_for_latency = false;
 	stop_metering_thread ();
 	
 	Port::PortDrop ();
@@ -982,6 +993,13 @@ AudioEngine::halted_callback (const char* why)
 bool
 AudioEngine::setup_required () const
 {
+	/* If there is only a single backend and it claims to be configured
+	 * already there is no setup to be done.
+	 *
+	 * Primarily for a case where there is only a JACK backend and
+	 * JACK is already running.
+	 */
+	 
 	if (_backends.size() == 1 && _backends.begin()->second->already_configured()) {
 		return false;
 	}
@@ -995,9 +1013,28 @@ AudioEngine::mtdm()
 	return _mtdm;
 }
 
+int
+AudioEngine::prepare_for_latency_measurement ()
+{
+	if (!running()) {
+		_started_for_latency = true;
+
+		if (start()) {
+			_started_for_latency = false;
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 void
 AudioEngine::start_latency_detection ()
 {
+	if (prepare_for_latency_measurement ()) {
+		return;
+	}
+
 	PortEngine& pe (port_engine());
 
 	delete _mtdm;
@@ -1026,26 +1063,32 @@ AudioEngine::start_latency_detection ()
 	_latency_signal_latency = 0;
 	lr = pe.get_latency_range (_latency_input_port, false);
 	_latency_signal_latency = lr.max;
+	cerr << "Input port lm = " << lr.max;
 	lr = pe.get_latency_range (_latency_output_port, true);
 	_latency_signal_latency += lr.max;
+	cerr << " output port lm = " << lr.max << endl;
 
-	cerr << "latency signal pathway = " << _latency_signal_latency << endl;
-	
 	/* all created and connected, lets go */
 
 	_mtdm = new MTDM (sample_rate());
 	_measuring_latency = true;
         _latency_flush_frames = samples_per_cycle();
 
-
 }
 
 void
 AudioEngine::stop_latency_detection ()
 {
+	cerr << "Stop LD\n";
+
+	_measuring_latency = false;
+
 	port_engine().unregister_port (_latency_output_port);
 	port_engine().unregister_port (_latency_input_port);
-	_measuring_latency = false;
+	
+	if (_started_for_latency) {
+		stop ();
+	}
 }
 
 void

libs/ardour/session.cc

@@ -289,13 +289,26 @@ Session::Session (AudioEngine &eng,
 	/* we need the audioengine to be up and usable to make much more
 	 * progress with construction, so lets get that started if it isn't already.
 	 */
-	
+
-	if (_engine.current_backend() == 0 || _engine.setup_required()) {
+	if (_engine.current_backend() == 0) {
+		/* backend is unknown ... */
 		boost::optional<int> r = AudioEngineSetupRequired (sr);
 		if (r.get_value_or (-1) != 0) {
 			destroy ();
 			throw failed_constructor();
 		}
+	} else if (_engine.setup_required()) {
+		/* backend is known, but setup is needed */
+		boost::optional<int> r = AudioEngineSetupRequired (sr);
+		if (r.get_value_or (-1) != 0) {
+			destroy ();
+			throw failed_constructor();
+		}
+	} else if (!_engine.running()) {
+		if (_engine.start()) {
+			destroy ();
+			throw failed_constructor ();
+		}
 	}
 
 	/* at this point the engine should be connected (i.e. interacting