Okay, today (and over part of the weekend) I ripped the RealTek driver
apart and put it back together again, this time in a hopefully working
form. The temporary patch version is at the following locations:

http://www.freebsd.org/~wpaul/RealTek/test/2.2  source for FreeBSD 2.2.x
http://www.freebsd.org/~wpaul/RealTek/test/3.0  source for FreeBSD 3.x/4.x

If you've been having problems with RealTek 8139 cards, please try this
version and let me know if it makes a differences. All of the main
changes are in the transmit code. I also think I know why the transmitter
was getting wedged. The sort answer: I'm a twit. The long answer:
when ifinit() was changed so that it warned about ifq_maxlen not being set
by the driver, I went in and set it to RL_TX_LIST_CNT - 1, which is
approximately what I'd done for the other drivers. However the RealTek
only has four transmit 'descriptors' which means the ifq_maxlen for the
interface was being set to the ridiculously low value of 3. This causes
transmissions of large packet sequences to quickly fill up the send
queue. (For example, try doing a ping -s 8100 <some host> and see if it
actually works. My bet is that it won't, because this will generate a
series of six or seven frames in rapid succession, and after the first
3 or 4, the queue fills up.)

In addition to fixing this, I also re-wrote rl_start() and rl_txeof()
to hopefully be a little simpler and less brain damaged. I still need
to fill in rl_txeoc() correctly, but once I know for sure that I've
fixed all the major problems, I can probably do that in an hour or two.

I experimented with this driver version using a FreeBSD 2.2.7 server and
a FreeBSD 3.0 client (sorry, it's all I had) and I couldn't get NFS
to hang. I also bombarded the server with a TCP stream from the client
while the NFS test was running and it didn't lock up.

-Bill

-- 
=============================================================================
-Bill Paul            (212) 854-6020 | System Manager, Master of Unix-Fu
Work:         wp...@ctr.columbia.edu | Center for Telecommunications Research
Home:  wp...@skynet.ctr.columbia.edu | Columbia University, New York City
=============================================================================
"Mulder, toads just fell from the sky!" "I guess their parachutes didn't open."
=============================================================================


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