From a8e8f7ba4328eb2ae630856af7c4277bd009b45c Mon Sep 17 00:00:00 2001
From: Dario Casalinuovo <b.vitruvio@gmail.com>
Date: Fri, 20 Jan 2017 22:23:55 +0100
Subject: [PATCH] Revert "MultiAudioNode: Fix and polish output locking issues"

This reverts commit 19da5e15c33f9a85d1e4ca0779f5082fd9d1eaf0.
---
 .../multi_audio/MultiAudioNode.cpp            | 31 +++++++++++++------
 .../multi_audio/MultiAudioNode.h              |  2 +-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.cpp b/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.cpp
index 2444794563..fc2287401e 100644
--- a/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.cpp
+++ b/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.cpp
@@ -173,7 +173,6 @@ MultiAudioNode::MultiAudioNode(BMediaAddOn* addon, const char* name,
 	BBufferConsumer(B_MEDIA_RAW_AUDIO),
 	BBufferProducer(B_MEDIA_RAW_AUDIO),
 	BMediaEventLooper(),
-	fRunOutput(false),
 	fBufferLock("multi audio buffers"),
 	fThread(-1),
 	fDevice(device),
@@ -1173,8 +1172,6 @@ MultiAudioNode::_HandleBuffer(const media_timed_event* event,
 		fprintf(stderr,"	<- LATE BUFFER : %" B_PRIdBIGTIME "\n", lateness);
 		buffer->Recycle();
 	} else {
-		BAutolock _(fBufferLock);
-
 		//WriteBuffer(buffer, *channel);
 		// TODO: This seems like a very fragile mechanism to wait until
 		// the previous buffer for this channel has been processed...
@@ -1780,13 +1777,18 @@ MultiAudioNode::_OutputThread()
 
 	// init the performance time computation
 	{
-		fBufferLock.Lock();
+		BAutolock locker(fBufferLock);
 		fTimeComputer.Init(fOutputPreferredFormat.u.raw_audio.frame_rate,
 			system_time());
-		fBufferLock.Unlock();
 	}
 
-	while (fRunOutput) {
+	while (true) {
+		// TODO: why this semaphore??
+		if (acquire_sem_etc(fBufferFreeSem, 1, B_RELATIVE_TIMEOUT, 0)
+				== B_BAD_SEM_ID) {
+			return B_OK;
+		}
+
 		BAutolock locker(fBufferLock);
 			// make sure the buffers don't change while we're playing with them
 
@@ -1834,6 +1836,9 @@ MultiAudioNode::_OutputThread()
 						_WriteZeros(*input, input->fBufferCycle);
 					//PRINT(("MultiAudioNode::Runthread WriteZeros\n"));
 				}
+
+				// mark buffer free
+				release_sem(fBufferFreeSem);
 			} else {
 				//PRINT(("playback_buffer_cycle non ok input : %i\n", i));
 			}
@@ -2043,14 +2048,21 @@ MultiAudioNode::_StartOutputThreadIfNeeded()
 	if (fThread >= 0)
 		return B_OK;
 
-	fRunOutput = true;
+	// allocate buffer free semaphore
+	fBufferFreeSem = create_sem(
+		fDevice->BufferList().return_playback_buffers - 1,
+		"multi_audio out buffer free");
+	if (fBufferFreeSem < B_OK)
+		return fBufferFreeSem;
 
 	PublishTime(-50, 0, 0);
 
 	fThread = spawn_thread(_OutputThreadEntry, "multi_audio audio output",
 		B_REAL_TIME_PRIORITY, this);
-	if (fThread < B_OK)
+	if (fThread < B_OK) {
+		delete_sem(fBufferFreeSem);
 		return fThread;
+	}
 
 	resume_thread(fThread);
 	return B_OK;
@@ -2061,8 +2073,7 @@ status_t
 MultiAudioNode::_StopOutputThread()
 {
 	CALLED();
-
-	fRunOutput = false;
+	delete_sem(fBufferFreeSem);
 
 	status_t exitValue;
 	wait_for_thread(fThread, &exitValue);
diff --git a/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.h b/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.h
index 0add2ffc6f..473c77b631 100644
--- a/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.h
+++ b/src/add-ons/media/media-add-ons/multi_audio/MultiAudioNode.h
@@ -208,7 +208,6 @@ private:
 
 private:
 	status_t			fInitStatus;
-	bool				fRunOutput;
 
 	BMediaAddOn*		fAddOn;
 	int32				fId;
@@ -228,6 +227,7 @@ private:
 		// not the defaults that are in the parameters
 	bigtime_t			fBufferPeriod;
 
+	sem_id				fBufferFreeSem;
 	thread_id			fThread;
 	MultiAudioDevice*	fDevice;
 	bool 				fTimeSourceStarted;