I am trying to bring up prbs31 testing between a ConnectX-5 NIC and an FPGA CX4 port. The cable is non-standard as it only has a QSFP+ plug on the NIC end (the fpga end is using a different connector standard). I need to know how to configure parameters such as TX diff swing (etc…) at the NIC end of the cable using mft mlxlink (I assume) to open up the eye at the RX end which is reported by the FPGA.
As background, the interface comes up fine when running as a CX4 100G (4x 25G lanes) connection, so I know that the cable and both ends of the link are fine, but I need to know how to configure the NIC for this eye scan test to see how much margin we have in both directions.