TX_FULL_MARK
(int)tx_ring_p->descs_pending - TX_FULL_MARK));
(int)tx_ring_p->descs_pending - TX_FULL_MARK));
(int)tx_ring_p->descs_pending - TX_FULL_MARK));
(int)tx_ring_p->descs_pending - TX_FULL_MARK));