sas_ex_discover_devices
res = sas_ex_discover_devices(dev, -1);
res = sas_ex_discover_devices(port->port_dev, -1);
res = sas_ex_discover_devices(child, -1);
res = sas_ex_discover_devices(dev, -1);
res = sas_ex_discover_devices(dev, phy_id);