ATH_RSSI_DUMMY_MARKER
sc->sc_halstats.ns_avgbrssi = ATH_RSSI_DUMMY_MARKER;
sc->sc_halstats.ns_avgrssi = ATH_RSSI_DUMMY_MARKER;
sc->sc_halstats.ns_avgtxrssi = ATH_RSSI_DUMMY_MARKER;
((x != ATH_RSSI_DUMMY_MARKER) ? (((x) * ((len) - 1) + (y)) / (len)) : (y))