Low Latency Ethernet 10G MAC (QSE): Receive pktstatus error 0x20 (bit 5)

Hi,

I'm currently debugging issues with the QSE 10G IP core embedded into an

FPGA (Arria10) connected via PCIe to the system CPU (PC).

Sometimes the RX mSGDMA reports this error:

RCV pktstatus 00000020 pktlength 00000558

...

My current best guess about the pktstatus read from the mSGDMA controller

(status from the response FIFO), is that it represents rx_status/error from the

MAC (MAC manual page 90):

avalon_st_rxstatus_error[]

Out 7 When set to 1, the respective bit indicates thefollowing error type in the RX frame.

• Bit 0: Undersized frame.

• Bit 1: Oversized frame.

• Bit 2: Payload length error.

• Bit 3: CRC error.

• Bit 4: Unused.

• Bit 5: Unused.

• Bit 6: PHY error.

The IP core presents the error status on this bus in the same clock cycle it asserts

the avalon_st_rxstatus_valid signal. The error status is invalid when an overflow

occurs.

Is this assumption correct? And if yes, 0x20 means bit 5 and this is "Unused" in the

table above. So what could this error mean?

Thanks,

Stefan