diff --git a/src/dev/copy_engine.cc b/src/dev/copy_engine.cc
index 3c759ac1d..feb0342de 100644
--- a/src/dev/copy_engine.cc
+++ b/src/dev/copy_engine.cc
@@ -110,7 +110,8 @@ CopyEngine::CopyEngineChannel::init()
 {
     Port *peer;
 
-    cePort = new DmaPort(ce, ce->sys);
+    cePort = new DmaPort(ce, ce->sys, ce->params()->min_backoff_delay,
+            ce->params()->max_backoff_delay);
     peer = ce->dmaPort->getPeer()->getOwner()->getPort("");
     peer->setPeer(cePort);
     cePort->setPeer(peer);
diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc
index cdba171a6..b3054a6ee 100644
--- a/src/dev/io_device.cc
+++ b/src/dev/io_device.cc
@@ -99,10 +99,11 @@ BasicPioDevice::addressRanges(AddrRangeList &range_list)
 }
 
 
-DmaPort::DmaPort(DmaDevice *dev, System *s)
+DmaPort::DmaPort(MemObject *dev, System *s, Tick min_backoff, Tick max_backoff)
     : Port(dev->name() + "-dmaport", dev), device(dev), sys(s),
       pendingCount(0), actionInProgress(0), drainEvent(NULL),
-      backoffTime(0), inRetry(false), backoffEvent(this)
+      backoffTime(0), minBackoffDelay(min_backoff),
+      maxBackoffDelay(max_backoff), inRetry(false), backoffEvent(this)
 { }
 
 bool
@@ -112,9 +113,9 @@ DmaPort::recvTiming(PacketPtr pkt)
         DPRINTF(DMA, "Received nacked %s addr %#x\n",
                 pkt->cmdString(), pkt->getAddr());
 
-        if (backoffTime < device->minBackoffDelay)
-            backoffTime = device->minBackoffDelay;
-        else if (backoffTime < device->maxBackoffDelay)
+        if (backoffTime < minBackoffDelay)
+            backoffTime = minBackoffDelay;
+        else if (backoffTime < maxBackoffDelay)
             backoffTime <<= 1;
 
         reschedule(backoffEvent, curTick + backoffTime, true);
@@ -138,10 +139,12 @@ DmaPort::recvTiming(PacketPtr pkt)
         state->numBytes += pkt->req->getSize();
         assert(state->totBytes >= state->numBytes);
         if (state->totBytes == state->numBytes) {
-            if (state->delay)
-                schedule(state->completionEvent, curTick + state->delay);
-            else
-                state->completionEvent->process();
+            if (state->completionEvent) {
+                if (state->delay)
+                    schedule(state->completionEvent, curTick + state->delay);
+                else
+                    state->completionEvent->process();
+            }
             delete state;
         }
         delete pkt->req;
@@ -159,8 +162,7 @@ DmaPort::recvTiming(PacketPtr pkt)
 }
 
 DmaDevice::DmaDevice(const Params *p)
-    : PioDevice(p), dmaPort(NULL), minBackoffDelay(p->min_backoff_delay),
-      maxBackoffDelay(p->max_backoff_delay)
+    : PioDevice(p), dmaPort(NULL)
 { }
 
 
@@ -221,8 +223,6 @@ void
 DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
                    uint8_t *data, Tick delay)
 {
-    assert(event);
-
     assert(device->getState() == SimObject::Running);
 
     DmaReqState *reqState = new DmaReqState(event, this, size, delay);
@@ -313,11 +313,14 @@ DmaPort::sendDma()
 
         DPRINTF(DMA, "--Received response for  DMA for addr: %#x size: %d nb: %d, tot: %d sched %d\n",
                 pkt->req->getPaddr(), pkt->req->getSize(), state->numBytes,
-                state->totBytes, state->completionEvent->scheduled());
+                state->totBytes,
+                state->completionEvent ? state->completionEvent->scheduled() : 0 );
 
         if (state->totBytes == state->numBytes) {
-            assert(!state->completionEvent->scheduled());
-            schedule(state->completionEvent, curTick + lat + state->delay);
+            if (state->completionEvent) {
+                assert(!state->completionEvent->scheduled());
+                schedule(state->completionEvent, curTick + lat + state->delay);
+            }
             delete state;
             delete pkt->req;
         }
diff --git a/src/dev/io_device.hh b/src/dev/io_device.hh
index 54128e48f..9ed287589 100644
--- a/src/dev/io_device.hh
+++ b/src/dev/io_device.hh
@@ -92,13 +92,14 @@ class DmaPort : public Port
         /** Amount to delay completion of dma by */
         Tick delay;
 
+
         DmaReqState(Event *ce, Port *p, Addr tb, Tick _delay)
             : completionEvent(ce), outPort(p), totBytes(tb), numBytes(0),
               delay(_delay)
         {}
     };
 
-    DmaDevice *device;
+    MemObject *device;
     std::list<PacketPtr> transmitList;
 
     /** The system that device/port are in. This is used to select which mode
@@ -119,6 +120,12 @@ class DmaPort : public Port
      * recived, decreases as responses are recived. */
     Tick backoffTime;
 
+    /** Minimum time that device should back off for after failed sendTiming */
+    Tick minBackoffDelay;
+
+    /** Maximum time that device should back off for after failed sendTiming */
+    Tick maxBackoffDelay;
+
     /** If the port is currently waiting for a retry before it can send whatever
      * it is that it's sending. */
     bool inRetry;
@@ -145,7 +152,7 @@ class DmaPort : public Port
     EventWrapper<DmaPort, &DmaPort::sendDma> backoffEvent;
 
   public:
-    DmaPort(DmaDevice *dev, System *s);
+    DmaPort(MemObject *dev, System *s, Tick min_backoff, Tick max_backoff);
 
     void dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
                    uint8_t *data, Tick delay);
@@ -256,8 +263,6 @@ class DmaDevice : public PioDevice
 {
    protected:
     DmaPort *dmaPort;
-    Tick minBackoffDelay;
-    Tick maxBackoffDelay;
 
   public:
     typedef DmaDeviceParams Params;
@@ -298,7 +303,8 @@ class DmaDevice : public PioDevice
             if (dmaPort != NULL)
                 fatal("%s: dma port already connected to %s",
                       name(), dmaPort->getPeer()->name());
-            dmaPort = new DmaPort(this, sys);
+            dmaPort = new DmaPort(this, sys, params()->min_backoff_delay,
+                    params()->max_backoff_delay);
             return dmaPort;
         } else
             return NULL;