From 22b50c1716bda71e8f97471e21ebcf6bde8bc57d Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 14 Mar 2022 14:02:09 -0600
Subject: [PATCH] ensure that Session handles tempo map changes synchronously
 in the main RT process thread

---
 libs/ardour/ardour/session.h   | 3 +--
 libs/ardour/audioengine.cc     | 8 +++++++-
 libs/ardour/session.cc         | 2 --
 libs/ardour/session_process.cc | 3 ---
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 8ca1665127..e616090f88 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1384,6 +1384,7 @@ protected:
 	void set_transport_speed (double speed);
 	void set_default_play_speed (double spd);
 	bool need_declick_before_locate () const;
+	void tempo_map_changed ();
 
 private:
 	int  create (const std::string& mix_template, BusProfile const *, bool unnamed);
@@ -1892,8 +1893,6 @@ private:
 	int  send_full_time_code (samplepos_t, pframes_t nframes);
 	void send_song_position_pointer (samplepos_t);
 
-	void          tempo_map_changed ();
-
 	/* edit/mix groups */
 
 	int load_route_groups (const XMLNode&, int);
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index c36316ee0a..c96952a36c 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -289,7 +289,13 @@ AudioEngine::process_callback (pframes_t nframes)
 		thread_init_callback (NULL);
 	}
 
-	Temporal::TempoMap::fetch ();
+	Temporal::TempoMap::SharedPtr current_map = Temporal::TempoMap::read ();
+	if (current_map != Temporal::TempoMap::use()) {
+		Temporal::TempoMap::set (current_map);
+		if (_session) {
+			_session->tempo_map_changed ();
+		}
+	}
 
 	/* This is for JACK, where the latency callback arrives in sync with
 	 * port registration (usually while ardour holds the process-lock
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 2c3fb69a7d..58c34e28bb 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -476,8 +476,6 @@ Session::Session (AudioEngine &eng,
 	Config->ParameterChanged.connect_same_thread (*this, boost::bind (&Session::config_changed, this, _1, false));
 	config.ParameterChanged.connect_same_thread (*this, boost::bind (&Session::config_changed, this, _1, true));
 
-	TempoMap::MapChanged.connect_same_thread (*this, boost::bind (&Session::tempo_map_changed, this));
-
 	if (was_dirty) {
 		DirtyChanged (); /* EMIT SIGNAL */
 	}
diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index f66ae0f6ab..422c01bc06 100644
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -1628,10 +1628,7 @@ Session::implement_master_strategy ()
 void
 Session::sync_cues ()
 {
-	std::cerr << "Need to sync cues!\n";
-
 	_locations->apply (*this, &Session::sync_cues_from_list);
-
 }
 
 struct LocationByTime