I don't know how many time-out problems exist in via-rhine.c, but the patch
below fixes at least one of them. It works for my VT6102 based card. I hope
some of you can confirm the fix (or let me know what other chips I broke).

Here's the error message the patch addresses:
Transmit timed out, status 0000, PHY status 782d, resetting...

The patch is slightly experimental and contains some changes and clean-ups
that are not directly related to the time out problem.

Patch description:
- Recover gracefully from TxAbort (the actual fix)
- Explicitly pick a backoff algorithm (alternative "fix")
- Remove full_duplex, duplex_lock, and advertising from netdev_private
- Make use of MII register names somewhat more consistent
- Update comment regarding config information at 0x78
- Move comment on *_desc_status where it belongs
- More comment details

Some information on stalling:

The time outs happened because the driver's handling of TxAbort was
incomplete: The transfer didn't get restarted. My initial fix was to
prevent TxAbort -- clearing bit 1 of ConfigD did the trick for me. The
stalling effect was gone.

The simple reason: The AMD backoff algorithm always triggered TxAborts,
the others didn't.

However, once I had the driver recover from TxAbort without waiting for the
time out reset, the AMD solution provided over 20% higher throughput than
the DEC algorithm. YMMV, depending on the specific setup. I'd vote for a
module parameter. For now, I hardcoded AMD: it's what the eeprom picks when
reloaded. Also, every other algorithm masked the TxAbort problem (by not
triggering any).

Incidentally, the VIA drivers clear bits 0-3 and set bit 3 of TxConfig for
all chips (the latter supposedly deals with backoff algorithms, too, but
it didn't seem to make a measurable difference on my system).

Patch is against 2.4.19-pre8. Feedback welcome.

Roger