TCP segmentation offload broken on bge

[Arto Huusko <arto.huusko%pp2.inet.fi@localhost>]

Hi,

TSO support in bge seems to be broken. Basic networking
does work, but with at least large overlapping transfers
things go wrong.

The bge is attached like this:

bge0 at pci2 dev 0 function 0: Broadcom BCM5787M Gigabit Ethernet
bge0: interrupting at ioapic0 pin 18 (irq 11)
bge0: ASIC BCM5754/5787 A2 (0xb002), Ethernet address 00:1b:38:2b:fc:30
bge0: setting short Tx thresholds
brgphy0 at bge0 phy 1: BCM5754/5787 1000BASE-T media interface, rev. 0

When it is first configured, the following error is shown:

bge0: block failed to stop: reg 0x1400, bit 0x00000002


One way to make things fail is to fetch something from network
to NFS mounted volume. The transfer grinds to halt immediately,
and soon an error that the NFS server is not responding is shown.
Tcpdump shows unrecognized response codes in the NFS stream.

Fetching the same stuff to a local disk does work.

When tso4 is disabled, everything seems to work without problems.