• Compare the issue across several devices or PCBs to ensure that the issue is not a one-off case.
• Try using an alternative link partner or test equipment and then compare results.
• Try swapping the optical module on a misperforming device and repeat the tests.
Perform these additional checks when using a device-specific transceiver:
• Directly monitor the following ports of the device-specific transceiver by attaching error counters to them, or by triggering on them using the Vivado Design Suite debug feature or an external logic analyzer.
rxdisperr
rxnotintable
These signals should not be asserted over the duration of a few seconds, minutes, or even hours. If they are frequently asserted, it might indicate an issue with the device-specific transceiver.
• Place the device-specific transceiver into parallel or serial loopback.
° If the core exhibits correct operation in device-specific transceiver serial loopback, but not when loopback is performed through an optical cable, it might indicate a faulty optical module.
° If the core exhibits correct operation in device-specific transceiver parallel loopback but not in serial loopback, this can indicate a device-specific transceiver issue.