Index: sys/cam/cam_sim.h
===================================================================
--- sys/cam/cam_sim.h
+++ sys/cam/cam_sim.h
@@ -142,5 +142,11 @@
 	return (sim->bus_id);
 }
 
+static __inline bool
+cam_sim_pollable(const struct cam_sim *sim)
+{
+	return (sim->sim_poll != NULL);
+}
+
 #endif /* _KERNEL */
 #endif /* _CAM_CAM_SIM_H */
Index: sys/cam/cam_xpt.c
===================================================================
--- sys/cam/cam_xpt.c
+++ sys/cam/cam_xpt.c
@@ -3203,6 +3203,9 @@
 	devq = sim->devq;
 	dev = start_ccb->ccb_h.path->device;
 
+	if (!cam_sim_pollable(sim))
+		return (0);
+
 	/*
 	 * Steal an opening so that no other queued requests
 	 * can get it before us while we simulate interrupts.
@@ -3226,13 +3229,16 @@
 xpt_pollwait(union ccb *start_ccb, uint32_t timeout)
 {
 
-	while (--timeout > 0) {
-		xpt_sim_poll(start_ccb->ccb_h.path->bus->sim);
-		if ((start_ccb->ccb_h.status & CAM_STATUS_MASK)
-		    != CAM_REQ_INPROG)
-			break;
-		DELAY(100);
-	}
+	if (cam_sim_pollable(start_ccb->ccb_h.path->bus->sim)) {
+		while (--timeout > 0) {
+			xpt_sim_poll(start_ccb->ccb_h.path->bus->sim);
+			if ((start_ccb->ccb_h.status & CAM_STATUS_MASK)
+			    != CAM_REQ_INPROG)
+				break;
+			DELAY(100);
+		}
+	} else
+		timeout = 0;
 
 	if (timeout == 0) {
 		/*