See the port list in Table: Transceiver I/O for a complete description of the diagnostic signals that are available to debug the RX.
If the Ethernet packets are being transmitted properly according to the 802.3 protocol, there should not be RX errors. However, the signal integrity of the received signals must be verified first.
The stat_rx_bip_err signals provide a per-lane indicator of signal quality. The stat_rx_hi_ber signal is asserted when the bit error rate is too high, according to the 802.3 protocol. The threshold is BER = 10-4.
To aid in debug, a local loopback can be performed at the transceiver level. This connects the TX SerDes to the RX SerDes and bypasses potential signal integrity problems. The received data can be checked against the transmitted packets to verify that the logic is operating properly.