rem: descriptor->wb_ctl = WB_MAX_FRAMELEN | WB_RXCTL_RLINK;
add: descriptor->wb_ctl |= WB_MAX_FRAMELEN | WB_RXCTL_RLINK;
context: wb_put_rx_descriptor(wb_desc *descriptor){	descriptor->wb_status = WB_RXSTAT_OWN;	descriptor->wb_ctl = WB_MAX_FRAMELEN | WB_RXCTL_RLINK;}