Index: head/sys/dev/mpr/mpr.c
===================================================================
--- head/sys/dev/mpr/mpr.c
+++ head/sys/dev/mpr/mpr.c
@@ -397,6 +397,7 @@
 	reqcr = MIN(reqcr, sc->facts->RequestCredit);
 
 	sc->num_reqs = prireqcr + reqcr;
+	sc->num_prireqs = prireqcr;
 	sc->num_replies = MIN(sc->max_replyframes + sc->max_evtframes,
 	    sc->facts->MaxReplyDescriptorPostQueueDepth) - 1;
 
@@ -1507,7 +1508,7 @@
 		/* XXX Is a failure here a critical problem? */
 		if (bus_dmamap_create(sc->buffer_dmat, 0, &cm->cm_dmamap)
 		    == 0) {
-			if (i <= sc->facts->HighPriorityCredit)
+			if (i <= sc->num_prireqs)
 				mpr_free_high_priority_command(sc, cm);
 			else
 				mpr_free_command(sc, cm);
Index: head/sys/dev/mpr/mpr_sas.c
===================================================================
--- head/sys/dev/mpr/mpr_sas.c
+++ head/sys/dev/mpr/mpr_sas.c
@@ -728,7 +728,7 @@
 {
 	struct mprsas_softc *sassc;
 	cam_status status;
-	int unit, error = 0;
+	int unit, error = 0, reqs;
 
 	MPR_FUNCTRACE(sc);
 	mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);
@@ -758,7 +758,8 @@
 	sc->sassc = sassc;
 	sassc->sc = sc;
 
-	if ((sassc->devq = cam_simq_alloc(sc->num_reqs)) == NULL) {
+	reqs = sc->num_reqs - sc->num_prireqs - 1;
+	if ((sassc->devq = cam_simq_alloc(reqs)) == NULL) {
 		mpr_dprint(sc, MPR_INIT|MPR_ERROR, "Cannot allocate SIMQ\n");
 		error = ENOMEM;
 		goto out;
@@ -766,7 +767,7 @@
 
 	unit = device_get_unit(sc->mpr_dev);
 	sassc->sim = cam_sim_alloc(mprsas_action, mprsas_poll, "mpr", sassc,
-	    unit, &sc->mpr_mtx, sc->num_reqs, sc->num_reqs, sassc->devq);
+	    unit, &sc->mpr_mtx, reqs, reqs, sassc->devq);
 	if (sassc->sim == NULL) {
 		mpr_dprint(sc, MPR_INIT|MPR_ERROR, "Cannot allocate SIM\n");
 		error = EINVAL;
Index: head/sys/dev/mpr/mprvar.h
===================================================================
--- head/sys/dev/mpr/mprvar.h
+++ head/sys/dev/mpr/mprvar.h
@@ -357,6 +357,7 @@
 
 	MPI2_IOC_FACTS_REPLY		*facts;
 	int				num_reqs;
+	int				num_prireqs;
 	int				num_replies;
 	int				fqdepth;	/* Free queue */
 	int				pqdepth;	/* Post queue */
Index: head/sys/dev/mps/mps.c
===================================================================
--- head/sys/dev/mps/mps.c
+++ head/sys/dev/mps/mps.c
@@ -394,6 +394,7 @@
 	reqcr = MIN(reqcr, sc->facts->RequestCredit);
 
 	sc->num_reqs = prireqcr + reqcr;
+	sc->num_prireqs = prireqcr;
 	sc->num_replies = MIN(sc->max_replyframes + sc->max_evtframes,
 	    sc->facts->MaxReplyDescriptorPostQueueDepth) - 1;
 
@@ -1453,7 +1454,7 @@
 
 		/* XXX Is a failure here a critical problem? */
 		if (bus_dmamap_create(sc->buffer_dmat, 0, &cm->cm_dmamap) == 0)
-			if (i <= sc->facts->HighPriorityCredit)
+			if (i <= sc->num_prireqs)
 				mps_free_high_priority_command(sc, cm);
 			else
 				mps_free_command(sc, cm);
Index: head/sys/dev/mps/mps_sas.c
===================================================================
--- head/sys/dev/mps/mps_sas.c
+++ head/sys/dev/mps/mps_sas.c
@@ -718,7 +718,7 @@
 {
 	struct mpssas_softc *sassc;
 	cam_status status;
-	int unit, error = 0;
+	int unit, error = 0, reqs;
 
 	MPS_FUNCTRACE(sc);
 	mps_dprint(sc, MPS_INIT, "%s entered\n", __func__);
@@ -748,7 +748,8 @@
 	sc->sassc = sassc;
 	sassc->sc = sc;
 
-	if ((sassc->devq = cam_simq_alloc(sc->num_reqs)) == NULL) {
+	reqs = sc->num_reqs - sc->num_prireqs - 1;
+	if ((sassc->devq = cam_simq_alloc(reqs)) == NULL) {
 		mps_dprint(sc, MPS_ERROR, "Cannot allocate SIMQ\n");
 		error = ENOMEM;
 		goto out;
@@ -756,7 +757,7 @@
 
 	unit = device_get_unit(sc->mps_dev);
 	sassc->sim = cam_sim_alloc(mpssas_action, mpssas_poll, "mps", sassc,
-	    unit, &sc->mps_mtx, sc->num_reqs, sc->num_reqs, sassc->devq);
+	    unit, &sc->mps_mtx, reqs, reqs, sassc->devq);
 	if (sassc->sim == NULL) {
 		mps_dprint(sc, MPS_INIT|MPS_ERROR, "Cannot allocate SIM\n");
 		error = EINVAL;
Index: head/sys/dev/mps/mpsvar.h
===================================================================
--- head/sys/dev/mps/mpsvar.h
+++ head/sys/dev/mps/mpsvar.h
@@ -345,6 +345,7 @@
 
 	MPI2_IOC_FACTS_REPLY		*facts;
 	int				num_reqs;
+	int				num_prireqs;
 	int				num_replies;
 	int				fqdepth;	/* Free queue */
 	int				pqdepth;	/* Post queue */