From 94e6164bc37abb977db082dd655adb096fc31989 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 11 Oct 2018 01:36:10 +0200
Subject: [PATCH] Add API to query backend realtime thread priority

---
 libs/ardour/ardour/audioengine.h        | 11 +++++++++++
 libs/backends/jack/jack_audiobackend.cc |  7 +++++++
 libs/backends/jack/jack_audiobackend.h  |  1 +
 3 files changed, 19 insertions(+)

diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index 6e7cdf7496..4548ad7391 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -106,6 +106,17 @@ class LIBARDOUR_API AudioEngine : public PortManager, public SessionHandlePtr
 	bool           in_process_thread ();
 	uint32_t       process_thread_count ();
 
+	/* internal backends
+	 * -20 : main thread
+	 * -21 : additional I/O threads e.g. MIDI
+	 * -22 : client/process threads
+	 *
+	 * search for
+	 * - pbd_realtime_pthread_create
+	 * - pbd_set_thread_priority
+	 */
+	virtual int    client_real_time_priority () { return -22; }
+
 	int            backend_reset_requested();
 	void           request_backend_reset();
 	void           request_device_list_update();
diff --git a/libs/backends/jack/jack_audiobackend.cc b/libs/backends/jack/jack_audiobackend.cc
index 616964c3f2..4258b9c23a 100644
--- a/libs/backends/jack/jack_audiobackend.cc
+++ b/libs/backends/jack/jack_audiobackend.cc
@@ -926,6 +926,13 @@ JACKAudioBackend::process_thread_count ()
 	return _jack_threads.size();
 }
 
+int
+JACKAudioBackend::client_real_time_priority ()
+{
+	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, 0);
+	return jack_client_real_time_priority (_priv_jack);
+}
+
 void*
 JACKAudioBackend::_start_process_thread (void* arg)
 {
diff --git a/libs/backends/jack/jack_audiobackend.h b/libs/backends/jack/jack_audiobackend.h
index 7d6d1bd977..e14396ea24 100644
--- a/libs/backends/jack/jack_audiobackend.h
+++ b/libs/backends/jack/jack_audiobackend.h
@@ -110,6 +110,7 @@ class JACKAudioBackend : public AudioBackend {
     int join_process_threads ();
     bool in_process_thread ();
     uint32_t process_thread_count ();
+		int client_real_time_priority ();
 
     void transport_start ();
     void transport_stop ();