Until I can get a clearer architecture from PHK about why he wants

the geometry code to grab a mutex that prohibits any driver on the
stack below it from sleeping, it's not safe to allow anything in
the top half of isp to sleep (excepting the thread that Fibre Channel
instances use to re-scan loops/fabrics).

sys/dev/isp/isp_freebsd.c

@@ -515,7 +515,9 @@ isp_intr_enable(void *arg)
 	struct ispsoftc *isp = arg;
 	if (isp->isp_role != ISP_ROLE_NONE) {
 		ENABLE_INTS(isp);
+#if	0
 		isp->isp_osinfo.intsok = 1;
+#endif
 	}
 	/* Release our hook so that the boot can continue. */
 	config_intrhook_disestablish(&isp->isp_osinfo.ehook);