RX_FIFO_THRESH
#define RX_FIFO_THRESH 7 /* 7 means NO threshold, Rx buffer level before first PCI xfer. */
#define RX_FIFO_THRESH 4 /* Rx buffer level before first PCI xfer. */
#define RX_FIFO_THRESH 4 /* Rx buffer level before first PCI xfer. */