Port: Only indicate that a SimpleTimingPort is drained if its send event is

not scheduled, as well as the transmit list being empty.

src/mem/cache/cache_impl.hh

@@ -1569,7 +1569,7 @@ Cache<TagStore>::MemSidePort::sendPacket()
             schedule(sendEvent, std::max(nextReady, curTick + 1));
         } else {
             // no more to send right now: if we're draining, we may be done
-            if (drainEvent) {
+            if (drainEvent && !sendEvent->scheduled()) {
                 drainEvent->process();
                 drainEvent = NULL;
             }

src/mem/tport.cc

@@ -155,7 +155,7 @@ SimpleTimingPort::sendDeferredPacket()
             schedule(sendEvent, time <= curTick ? curTick+1 : time);
         }
 
-        if (transmitList.empty() && drainEvent) {
+        if (transmitList.empty() && drainEvent && !sendEvent->scheduled()) {
             drainEvent->process();
             drainEvent = NULL;
         }
@@ -195,7 +195,7 @@ SimpleTimingPort::processSendEvent()
 unsigned int
 SimpleTimingPort::drain(Event *de)
 {
-    if (transmitList.size() == 0)
+    if (transmitList.size() == 0 && !sendEvent->scheduled())
         return 0;
     drainEvent = de;
     return 1;