Index: amd64/amd64/busdma_machdep.c
===================================================================
RCS file: /home/ncvs/src/sys/amd64/amd64/busdma_machdep.c,v
retrieving revision 1.86
diff -u -u -r1.86 busdma_machdep.c
--- amd64/amd64/busdma_machdep.c	15 Jul 2008 03:34:49 -0000	1.86
+++ amd64/amd64/busdma_machdep.c	12 Oct 2008 15:09:53 -0000
@@ -616,6 +616,7 @@
 		if (flags & BUS_DMA_NOWAIT) {
 			if (reserve_bounce_pages(dmat, map, 0) != 0) {
 				mtx_unlock(&bounce_lock);
+				CTR0(KTR_BUSDMA, "*** NO BOUNCE ***\n");
 				return (ENOMEM);
 			}
 		} else {
@@ -727,11 +728,24 @@
 	    __func__, dmat, dmat->flags, error, nsegs + 1);
 
 	if (error == EINPROGRESS) {
+		CTR0(KTR_BUSDMA, "*** IN PROGRESS");
 		return (error);
 	}
+ 
+	if (error == EFBIG) {
+		CTR0(KTR_BUSDMA, "*** 2 BIG");
+	}
+
+	if (error == ENOMEM) {
+		CTR0(KTR_BUSDMA, "*** NOMEM");
+	}
+
 
-	if (error)
+	if (error) {
+		CTR3(KTR_BUSDMA, "%s: *** CALLBACK called with error %x (%d)",
+		    __func__, error, error);
 		(*callback)(callback_arg, dmat->segments, 0, error);
+	}
 	else
 		(*callback)(callback_arg, dmat->segments, nsegs + 1, 0);
 
@@ -739,8 +753,10 @@
 	 * Return ENOMEM to the caller so that it can pass it up the stack.
 	 * This error only happens when NOWAIT is set, so deferal is disabled.
 	 */
-	if (error == ENOMEM)
+	if (error == ENOMEM) {
+		CTR0(KTR_BUSDMA, "*** NOMEM");
 		return (error);
+	}
 
 	return (0);
 }
Index: dev/ata/ata-dma.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/ata/ata-dma.c,v
retrieving revision 1.157
diff -u -u -r1157 ata-dma.c
--- dev/ata/ata-dma.c	9 Oct 2008 12:56:57 -0000	1.157
+++ dev/ata/ata-dma.c	13 Oct 2008 15:28:23 -0000
@@ -263,6 +263,9 @@
     struct ata_dmasetprd_args dspa;
     int error;
 
+    error = 0; 
+    bzero(&dspa, sizeof(struct ata_dmasetprd_args));
+
     ATA_DEBUG_RQ(request, "dmaload");
 
     if (request->dma) {
@@ -291,16 +294,31 @@
     /* set our slot, unit for simplicity XXX SOS NCQ will change that */
     request->dma = &ch->dma.slot[atadev->unit];
 
-    if (addr)
-	dspa.dmatab = addr;
-    else
-	dspa.dmatab = request->dma->sg;
+    if (addr) 
+      dspa.dmatab = addr;
+    else 
+      dspa.dmatab = request->dma->sg;
+    
+    if (dspaerror) 
+	 device_printf(request->dev, "ATA DMA dspa error set \n");
 
     if ((error = bus_dmamap_load(request->dma->data_tag, request->dma->data_map,
 				 request->data, request->bytecount,
 				 ch->dma.setprd, &dspa, BUS_DMA_NOWAIT)) ||
 				 (error = dspa.error)) {
-	device_printf(request->dev, "FAILURE - load data\n");
+	    device_printf(request->dev, "FAILURE - load data\n");
+	    device_printf(request->dev, "ATA error %x\n", error);
+	    device_printf(request->dev, "ATA dspa error %x\n", dspa.error);
+
+	    device_printf(request->dev, "ATA request dma %p dspa %p\n", 
+		request->dma, dspa.dmatab);
+
+
+	if (addr) 
+		device_printf(request->dev, "ATA DMA addr set\n");
+	else 
+		device_printf(request->dev, "ATA DMA addr not set\n");
+	panic("SHOULD NOT HAPPEN");
 	goto error;
     }