From 96f659446cf0d0cf5c6091449fd9a70c62e516d8 Mon Sep 17 00:00:00 2001
From: Torben Hohn <torbenh@gmx.de>
Date: Tue, 31 Mar 2009 17:56:02 +0200
Subject: [PATCH] be a bit more careful to not trigger race conditions in flash

---
 flashsupport.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/flashsupport.c b/flashsupport.c
index a88bf1c..fe0be51 100644
--- a/flashsupport.c
+++ b/flashsupport.c
@@ -193,6 +193,7 @@ extern "C" {
 #ifdef JACK
 #include <jack/jack.h>
 #include <jack/ringbuffer.h>
+#include <jack/thread.h>
 #include <samplerate.h>
 #include <semaphore.h>
 #endif
@@ -1082,11 +1083,16 @@ static void *jack_flash_thread( void *arg )
 	size_t bufsize = 2*flash_frames * sizeof( int16_t );
 	int16_t *buffer = alloca( bufsize );
 
+	sem_wait( &(p->semaphore) );
+	usleep( 50 );
+
 	while( !p->quit ) {
 		sem_wait( &(p->semaphore) );
 		FPI_SoundOutput_FillBuffer(p, (char*) buffer, bufsize);
-		jack_ringbuffer_write( p->buffer, (char*)buffer, bufsize );
+		if( jack_ringbuffer_write( p->buffer, (char*)buffer, bufsize ) != bufsize )
+			printf( "something is wrong\n" );
 	}
+
 	return NULL;
 }
 
@@ -1113,7 +1119,6 @@ static int jack_process_cb( jack_nframes_t nframes, void *arg )
 		return 0;
 	}
 
-        //FPI_SoundOutput_FillBuffer(p, (char*) buffer, bufsize);
 	if( jack_ringbuffer_read( p->buffer, (char *)buffer, bufsize ) != bufsize ) {
 		printf( "Something is pretty wrong :( \n" );
 		return 0;
@@ -1159,6 +1164,7 @@ static void *FPX_SoundOutput_Open(void) {
     int jack_rate;
     int flash_frames;
     size_t bufsize;
+    int i;
 
     /* Unfortunately we cannot report any useful error string back to
      * Flash. It would be highly preferable if Flash supported some
@@ -1182,10 +1188,21 @@ static void *FPX_SoundOutput_Open(void) {
     flash_frames = jack_get_buffer_size( p->client ) * 44100 / jack_rate;
     bufsize = 2*flash_frames * sizeof( int16_t );
 
-    p->buffer = jack_ringbuffer_create( bufsize * 2 );
-    sem_init( &(p->semaphore), 0, 2 );
+    p->buffer = jack_ringbuffer_create( bufsize * 6 );
+    sem_init( &(p->semaphore), 0, 0 );
 
     pthread_create( &(p->tid), NULL, jack_flash_thread, p );
+#if 0 
+// This seems to trigger a race condition in flash.
+
+    jack_client_create_thread( p->client,
+		    &(p->tid),
+		    (jack_client_real_time_priority( p->client ) == -1) ? 1 : (jack_client_real_time_priority( p->client ) - 1),
+		    (jack_client_real_time_priority( p->client ) == -1) ? 0 : 1,
+		    jack_flash_thread,
+		    p );
+#endif
+
 
     /* Second, initialize the connection context */
     if (!(p->port_l = jack_port_register( p->client, "out1", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0)) )
@@ -1201,6 +1218,13 @@ static void *FPX_SoundOutput_Open(void) {
     snprintf( namebuf, 99, "%s:out2", jack_get_client_name( p->client ) );
     jack_connect( p->client, namebuf, "system:playback_2" );
 
+    // Now start the fill thread.
+    // the semaphore represents the number of writeable buffers in
+    // the ringbuffer. we add 1 for the initial sem_wait.
+
+    for(i=0; i<( 5 + 1 ); i++ )
+	    sem_post( &(p->semaphore) );
+
     return p;
 
 fail:
-- 
2.11.4.GIT