r312348: igb broken: reporting wrong linkspeed!

[Hartmann, O.]

12-CURRENT (FreeBSD 12.0-CURRENT #74 r312348: Tue Jan 17 19:54:58 CET
2017 am64) reports the wrong linkspeed on a dualport Intel i350 NIC:

igb0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
1500
options=653dbb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,LRO,WOL_UCAST,WOL_MCAST,WOL_MAGIC,VLAN_HWFILTER,VLAN_HWTSO,RXCSUM_IPV6,TXCSUM_IPV6>
ether xx:xx:xx:xx:xx:xx inet 192.168.0.111 netmask 0xffffff00 broadcast
192.168.0.255 nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

The swith the NIC is connected to reports 1 GBit. I checked with two
switches, FreeBSD reports bullshit on that subject.

I also realised severe problems of this Intel i350 dual NIC cards with
FreeBSD (we use this NIC type as a standard and so we have plenty, all
with the same issue). When the NIC negotiates its linkspeed, it very
often fall back to 100 MBit. This behaviour is not predictable, but it
occurs with a SoHo smart managed Netgear GS110TBv2 and some of our
Cisco Catalyst switches at work (some 35XX and 29XX, I do not know the
exact type).

Regards,

oh