move all responsibility for autostart into StartupFSM and out of engine dialog

3 files changed, 23 insertions, 22 deletions

diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index 182a931cef..6cbe040371 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -471,18 +471,6 @@ EngineControl::config_parameter_changed (std::string const & p)
 }
 
 bool
-EngineControl::try_autostart ()
-{
-	if (!start_stop_button.get_sensitive()) {
-		return false;
-	}
-	if (ARDOUR::AudioEngine::instance()->running()) {
-		return true;
-	}
-	return start_engine ();
-}
-
-bool
 EngineControl::start_engine ()
 {
 	if (push_state_to_backend (true) != 0) {
diff --git a/gtk2_ardour/engine_dialog.h b/gtk2_ardour/engine_dialog.h
index 7592d4e9a8..5d3d6854d9 100644
--- a/gtk2_ardour/engine_dialog.h
+++ b/gtk2_ardour/engine_dialog.h
@@ -55,7 +55,6 @@ public:
 	bool set_state (const XMLNode&);
 
 	void set_desired_sample_rate (uint32_t);
-	bool try_autostart ();
 
 private:
 	Gtk::Notebook notebook;
diff --git a/gtk2_ardour/startup_fsm.cc b/gtk2_ardour/startup_fsm.cc
index 599eb0e337..7d05ca051a 100644
--- a/gtk2_ardour/startup_fsm.cc
+++ b/gtk2_ardour/startup_fsm.cc
@@ -425,21 +425,35 @@ StartupFSM::start_audio_midi_setup ()
 	}
 
 	if (setup_required) {
-		if (!session_is_new && session_existing_sample_rate > 0) {
-			audiomidi_dialog.set_desired_sample_rate (session_existing_sample_rate);
-		}
 
-		if (!session_is_new && (Config->get_try_autostart_engine () || g_getenv ("ARDOUR_TRY_AUTOSTART_ENGINE"))) {
+		/* Note: if autostart is enabled, and starting the engine is
+		 * successful, but the session SR differs, there will be no
+		 * chance to reset it.
+		 *
+		 * We could change this trivially with a call to
+		 * AudioEngine::set_sample_rate(), but that opens a can of
+		 * worms about policy, UX, GUI and more, because it isn't clear
+		 * whether that's the correct thing to do. So for now (Nov
+		 * 2019) we simply try the autostart if the user asked for it,
+		 * and if necessary a session SR mismatch dialog will appear
+		 * during loading.
+		 */
 
-			audiomidi_dialog.try_autostart ();
+		if (!session_is_new && (Config->get_try_autostart_engine () || g_getenv ("ARDOUR_TRY_AUTOSTART_ENGINE"))) {
 
-			if (ARDOUR::AudioEngine::instance()->running()) {
-				DEBUG_TRACE (DEBUG::GuiStartup, "autostart successful, audio/MIDI setup dialog not required\n");
-				engine_running ();
-				return;
+			if (!AudioEngine::instance()->start ()) {
+				if (ARDOUR::AudioEngine::instance()->running()) {
+					DEBUG_TRACE (DEBUG::GuiStartup, "autostart successful, audio/MIDI setup dialog not required\n");
+					engine_running ();
+					return;
+				}
 			}
 		}
 
+		if (!session_is_new && session_existing_sample_rate > 0) {
+			audiomidi_dialog.set_desired_sample_rate (session_existing_sample_rate);
+		}
+
 		show_audiomidi_dialog ();
 		DEBUG_TRACE (DEBUG::GuiStartup, "audiomidi shown and waiting\n");