Index: sys/cam/cam_periph.c
===================================================================
--- sys/cam/cam_periph.c
+++ sys/cam/cam_periph.c
@@ -770,6 +770,7 @@
 
 	if (periph->flags & CAM_PERIPH_NEW_DEV_FOUND) {
 		union ccb ccb;
+		int arglen;
 		void *arg;
 
 		memset(&ccb, 0, sizeof(ccb));
@@ -779,17 +780,20 @@
 			xpt_setup_ccb(&ccb.ccb_h, periph->path, CAM_PRIORITY_NORMAL);
 			xpt_action(&ccb);
 			arg = &ccb;
+			arglen = sizeof(ccb.cgd);
 			break;
 		case AC_PATH_REGISTERED:
 			xpt_path_inq(&ccb.cpi, periph->path);
 			arg = &ccb;
+			arglen = sizeof(ccb.cpi);
 			break;
 		default:
 			arg = NULL;
+			arglen = 0;
 			break;
 		}
-		periph->deferred_callback(NULL, periph->deferred_ac,
-					  periph->path, arg);
+		xpt_deferred_callback(periph->deferred_callback,
+		    periph->deferred_ac, periph->path, arg, arglen);
 	}
 	xpt_free_path(periph->path);
 	free(periph, M_CAMPERIPH);