Looking into new BSDI 3com driver, I noticed insteresting difference
in setting TX space threshold:

BSDI: (EF_NWEINT means card of 590 family)

         * Check if there is enough free space in TX buffer
         */
        i = inw(base+EF1_TXFREE) - 4;   /* exclude preamble */
        if (i < len) {  /* not enough */
               i = len + 4;
               if (sc->ef_flags & EF_NWEINT)
!!!!!                       i >>= 2;
               outw(base+EF_CMD, EFC_TXAVAIL | i);
                ifp->if_flags |= IFF_OACTIVE;

NetBSD:

        if (bus_io_read_2(bc, ioh, EP_W1_FREE_TX) < len + pad + 4) {
                bus_io_write_2(bc, ioh, EP_COMMAND,
                    SET_TX_AVAIL_THRESH | (len + pad + 4));
                /* not enough room in FIFO */
                ifp->if_flags |= IFF_OACTIVE;



-- 
Zdenek Salvet                                              salvet@ics.muni.cz 
----------------------------------------------------------------------------
           If God had meant for us to be in the Army,
         we would have been born with green, baggy skin.