BMediaEventLooper: Return to simple lateness computation

* Remove enqueue_time again.
* Lateness seems generally useless. No way to get something useful
experimentally. The commit noise however was useful, the port wait is
behaving more in accordance with the lateness calculus.
* Fixes #12817 and possibly #12594.

headers/os/media/TimedEventQueue.h

@@ -38,9 +38,8 @@ struct media_timed_event {
 			int32				data;
 			int64				bigdata;
 			char				user_data[64];
-			bigtime_t			enqueue_time;
 
-			uint32				_reserved_media_timed_event_[6];
+			uint32				_reserved_media_timed_event_[8];
 };
 
 

src/kits/media/MediaEventLooper.cpp

@@ -239,19 +239,13 @@ BMediaEventLooper::ControlLoop()
 			if (err == B_OK) {
 				// The general idea of lateness is to allow
 				// the client code to detect when the buffer
-				// is handled late or early. What we add is
+				// is handled late or early.
-				// that the code log the time at which the
+				bigtime_t lateness = TimeSource()->RealTime() - waitUntil;
-				// current event is added to the queue. This
+				// Maximum amount of lateness we tolerate
-				// allow us to detect cyclic/stagnant latency
+				if (lateness < 3000L)
-				// in the meantime, so that the client can
+					lateness = 0;
-				// notify to the producer only the portion
+
-				// that might be attributable.
+				DispatchEvent(&event, lateness, hasRealtime);
-				bigtime_t lateness = waitUntil - TimeSource()->RealTime();
-				if (lateness < 0 && event.enqueue_time > waitUntil) {
-					lateness = event.enqueue_time
-						- TimeSource()->RealTime();
-				}
-				DispatchEvent(&event, -lateness, hasRealtime);
 			}
 		} else if (err != B_OK)
 			return;

src/kits/media/TimedEventQueuePrivate.cpp

@@ -78,9 +78,6 @@ _event_queue_imp::AddEvent(const media_timed_event &event)
 		 return B_BAD_VALUE;
 	}
 
-	const_cast<media_timed_event&>(event).enqueue_time
-		= BTimeSource::RealTime();
-
 	//create a new queue
 	if (fFirstEntry == NULL) {
 		ASSERT(fEventCount == 0);