Dear wb,
In my Linux case with Supermicro X10SDV-4C-TLN4F and HPE 1950 24G 2SFP+ 2XGT Switch,
following two methods make both intefaces are up with 10Gbps.
= Increase the interface MTU value to 9216(HP 1950 series default and maximum value)
# ifconfig eno3 mtu 9216
# ifconfig eno4 mtu 9216
= Set the interface to advertise only 10000baseT Full in autonegotiation.
# ethtool -s eno3 advertise 0x1000
# ethtool -s eno4 advertise 0x1000
But in FreeBSD, increasing only mtu values did not make intefaces are up with 10Gbps.
Do you Intel have plan for updating FreeBSD driver for X552/X557?