pmpasync
static void pmpasync(void *callback_arg, uint32_t code,
status = xpt_register_async(AC_FOUND_DEVICE, pmpasync, NULL, NULL);
xpt_register_async(0, pmpasync, periph, periph->path);
path, pmpasync,
AC_SCSI_AEN, pmpasync, periph, periph->path);