tx v2 error 0x6204<UNDERFLOW> - is this a new feature?

[Pyun YongHyeon]

On Tue, Jan 11, 2011 at 04:16:45PM -0800, fbsdmail at dnswatch.com wrote:
> 
> On Tue, January 11, 2011 10:33 am, Pyun YongHyeon wrote:

[...]

> >>>> Does the link partner also agree on the resolved
> >>>> duplex(half-duplex)? It's not common to see half-duplex in these
> >>>> days. Please make sure link partner is also using auto-negotiation.
> >>>>
> >>>>
> >>>>
> >>>
> >>> I thought that odd, as well. Both kerns have as nearly the same
> >>> options as is possible. Because the 8.1/amd64 is intended as a
> >>> replacement for the 8.0/i386. They're both on the same switch.
> >>>
> >>
> >> OK. Sorry, it just occurred to me that they /aren't/ both 10/100's
> >> The 8.1/amd64 (nfe0) is 10/100/1000, which might account for the
> >> half-dup. Just thought I'd mention it - but I'm sure you already
> >> discovered that :P
> >>
> >
> > I don't know any auto-negotiation issues of ciphy(4) so please
> > verify whether the switch sees the same resolved speed/duplex. If you
> > manually configured switch port to use 100Mbps/full-duplex it would create
> > problems since resolved duplex for the parallel detection is normally
> > half-duplex. This will cause duplex mismatch and you will see lots of
> > unexpected problems. If both parties use the same forced media
> > configuration in 10/100Mbps mode it would work but nfe(4) has one
> > unresolved issue for that case(mainly due to lack of documentation).
> > Without
> > auto-negotiation, some nfe(4) controllers do not work correctly.
> >
> > nfe(4) also supports hardware MAC counters for supported controllers and I
> > think your controller supports that. See what counters you have with
> > "sysctl dev.nfe.0.stats".
> I'm going to be away for a couple of hours.
> Here's a dump of sysctl dev.nfe.0.stats, in the meantime:
> 
> dev.nfe.0.stats.rx.frame_errors: 0
> dev.nfe.0.stats.rx.extra_bytes: 0
> dev.nfe.0.stats.rx.late_cols: 0
> dev.nfe.0.stats.rx.runts: 0
> dev.nfe.0.stats.rx.jumbos: 0
> dev.nfe.0.stats.rx.fifo_overuns: 0
> dev.nfe.0.stats.rx.crc_errors: 0
> dev.nfe.0.stats.rx.fae: 0
> dev.nfe.0.stats.rx.len_errors: 0
> dev.nfe.0.stats.rx.unicast: 711887
> dev.nfe.0.stats.rx.multicast: 0
> dev.nfe.0.stats.rx.broadcast: 36072
> dev.nfe.0.stats.tx.octets: 400617598
> dev.nfe.0.stats.tx.zero_rexmits: 420611
> dev.nfe.0.stats.tx.one_rexmits: 171560
> dev.nfe.0.stats.tx.multi_rexmits: 64390

Two counters above clearly indicates there are collisions in link.
Check switch configuration and make it use auto-negotiation.

> dev.nfe.0.stats.tx.late_cols: 0
> dev.nfe.0.stats.tx.fifo_underuns: 0
> dev.nfe.0.stats.tx.carrier_losts: 0
> dev.nfe.0.stats.tx.excess_deferrals: 0
> dev.nfe.0.stats.tx.retry_errors: 182
> 
> Thank you for all your time and consideration Pyun YongHyeon.
> 
> --Chris