Index: /trunk/src/VBox/Devices/Storage/DevAHCI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 50031)
+++ /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 50032)
@@ -480,4 +480,6 @@
     /** Bitmap for new queued tasks (Guest -> R3). */
     volatile uint32_t               u32TasksNew;
+    /** Bitmap of tasks which must be redone because of a non fatal error. */
+    volatile uint32_t               u32TasksRedo;
 
     /** Current command slot processed.
@@ -486,5 +488,5 @@
     volatile uint32_t               u32CurrentCommandSlot;
 
-#if HC_ARCH_BITS == 32
+#if HC_ARCH_BITS == 64
     uint32_t                        u32Alignment2;
 #endif
@@ -1973,4 +1975,5 @@
 
     pAhciPort->u32TasksNew = 0;
+    pAhciPort->u32TasksRedo = 0;
     pAhciPort->u32TasksFinished = 0;
     pAhciPort->u32QueuedTasksFinished = 0;
@@ -5918,5 +5921,5 @@
             }
             else
-                ASMAtomicOrU32(&pAhciPort->u32TasksNew, RT_BIT_32(pAhciReq->uTag));
+                ASMAtomicOrU32(&pAhciPort->u32TasksRedo, RT_BIT_32(pAhciReq->uTag));
         }
         else
@@ -7499,8 +7502,11 @@
         PAHCIPort pAhciPort = &pAhci->ahciPort[i];
 
-        if (pAhciPort->u32TasksNew)
+        if (pAhciPort->u32TasksRedo)
         {
             PDEVPORTNOTIFIERQUEUEITEM pItem = (PDEVPORTNOTIFIERQUEUEITEM)PDMQueueAlloc(pAhci->CTX_SUFF(pNotifierQueue));
             AssertMsg(pItem, ("Allocating item for queue failed\n"));
+
+            pAhciPort->u32TasksNew |= pAhciPort->u32TasksRedo;
+            pAhciPort->u32TasksRedo = 0;
 
             Assert(pAhciPort->fRedo);
Index: /trunk/src/VBox/Devices/testcase/tstDeviceStructSizeRC.cpp
===================================================================
--- /trunk/src/VBox/Devices/testcase/tstDeviceStructSizeRC.cpp	(revision 50031)
+++ /trunk/src/VBox/Devices/testcase/tstDeviceStructSizeRC.cpp	(revision 50032)
@@ -1211,4 +1211,5 @@
     GEN_CHECK_OFF(AHCIPort, u32QueuedTasksFinished);
     GEN_CHECK_OFF(AHCIPort, u32TasksNew);
+    GEN_CHECK_OFF(AHCIPort, u32TasksRedo);
     GEN_CHECK_OFF(AHCIPort, u32CurrentCommandSlot);
     GEN_CHECK_OFF(AHCIPort, pDrvBase);