diff --git a/stepmania/src/RageSoundManager.cpp b/stepmania/src/RageSoundManager.cpp
index f097574b07..6ecb6b981d 100644
--- a/stepmania/src/RageSoundManager.cpp
+++ b/stepmania/src/RageSoundManager.cpp
@@ -32,6 +32,8 @@ RageSoundManager::RageSoundManager(CString drivers)
 		SOUNDMAN = NULL;
 		throw;
 	}
+
+	pos_map_queue.reserve( 1024 );
 }
 
 RageSoundManager::~RageSoundManager()
@@ -75,6 +77,9 @@ int64_t RageSoundManager::GetPosition( const RageSoundBase *snd ) const
 void RageSoundManager::Update(float delta)
 {
 	LockMut(lock);
+
+	FlushPosMapQueue();
+
 	while(!sounds_to_delete.empty())
 	{
 		delete *sounds_to_delete.begin();
@@ -105,6 +110,42 @@ void RageSoundManager::UnregisterSound( RageSound *p )
 	all_sounds.erase( p );
 }
 
+void RageSoundManager::CommitPlayingPosition( int ID, int64_t frameno, int pos, int got_frames )
+{
+	/* This can be called from realtime threads; don't lock any mutexes. */
+	queued_pos_map_t p;
+	p.ID = ID;
+	p.frameno = frameno;
+	p.pos = pos;
+	p.got_frames = got_frames;
+
+	pos_map_queue.write( &p, 1 );
+}
+
+void RageSoundManager::FlushPosMapQueue()
+{
+	LockMut(SOUNDMAN->lock);
+	queued_pos_map_t p;
+
+	while( pos_map_queue.read( &p, 1 ) )
+	{
+		/* Find the sound with p.ID. */
+		set<RageSound *>::iterator it;
+		for( it = all_sounds.begin(); it != all_sounds.end(); ++it )
+			if( (*it)->GetID() == p.ID )
+				break;
+
+		/* If we can't find the ID, the sound was probably deleted before we got here. */
+		if( it == all_sounds.end() )
+		{
+			LOG->Trace("ignored unknown (stale?) commit ID %i", p.ID);
+			continue;
+		}
+
+		(*it)->CommitPlayingPosition( p.frameno, p.pos, p.got_frames );
+	}
+}
+
 float RageSoundManager::GetPlayLatency() const
 {
 	return driver->GetPlayLatency();
diff --git a/stepmania/src/RageSoundManager.h b/stepmania/src/RageSoundManager.h
index c859fa6fe6..99c58510a4 100644
--- a/stepmania/src/RageSoundManager.h
+++ b/stepmania/src/RageSoundManager.h
@@ -5,6 +5,7 @@
 #include <map>
 #include "SDL_utils.h"
 #include "RageThreads.h"
+#include "RageUtil_CircularBuffer.h"
 
 class RageSound;
 class RageSoundBase;
@@ -24,6 +25,13 @@ class RageSoundManager
 
 	/* Prefs: */
 	float MixVolume;
+	struct queued_pos_map_t
+	{
+		int ID, pos, got_frames;
+		int64_t frameno;
+	};
+
+	CircBuf<queued_pos_map_t> pos_map_queue;
 
 public:
 	RageMutex lock;
@@ -40,6 +48,8 @@ public:
 	int64_t GetPosition( const RageSoundBase *snd ) const;	/* used by RageSound */
 	int RegisterSound( RageSound *p );		/* used by RageSound */
 	void UnregisterSound( RageSound *p );	/* used by RageSound */
+	void CommitPlayingPosition( int ID, int64_t frameno, int pos, int got_bytes );	/* used by drivers */
+	void FlushPosMapQueue();				/* used by RageSound */
 	float GetPlayLatency() const;
 	int GetDriverSampleRate( int rate ) const;
 	const set<RageSound *> &GetPlayingSounds() const { return playing_sounds; }