ENVY24HT_MT_PCNT
regno = ENVY24HT_MT_PCNT;
device_printf(sc->dev, "PCNT:%ld\n", envy24ht_rdmt(sc, ENVY24HT_MT_PCNT, 2));
ptr = dsize - envy24ht_rdmt(sc, ENVY24HT_MT_PCNT, 2) - 1;
envy24ht_wrmt(sc, ENVY24HT_MT_PCNT, (uint32_t)(segs->ds_len / 4 - 1), 2);