Date: Tue, 07 Sep 1999 20:16:13 -0700 From: Jason Thorpe <thorpej@nas.nasa.gov> To: Bill Paul <wpaul@skynet.ctr.columbia.edu> Cc: hackers@freebsd.org Subject: Re: Tulip device driver question Message-ID: <199909080316.UAA21624@lestat.nas.nasa.gov>
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On Tue, 7 Sep 1999 21:13:22 -0400 (EDT)
Bill Paul <wpaul@skynet.ctr.columbia.edu> wrote:
> Well, the older chipsets make it even harder on you: you have to know
> just the right way to twiddle the bits in the GPIO register in order to
> program the media settings, and to figure that out you're supposed to
> read the media description from the SROM, which is sometimes wrong.
> This opens up a whole other set of quirks.
Yah. This is pretty annoying. At least DEC spec'd it to be in the SROM :-)
When it's wrong, the `de' driver gets it wrong, too. Linux actually quirks
some boards which have incorrect SROM settings. I guess someone was willing
to trace the traces on the boards (ick!).
> I'm assuming you actually have a Winbond card. If you do, try this for
Yah, some Unicom card, I think.
> me: connect the Winbond to a link partner who's media settings you can
[ . . . snip . . . ]
> Winbond that if I changed the link partner's speed settings, it would
> start DMAing all kinds of crap into the host's memory. Furthermore, I
> think it ignores the RX buffer lengths specified in the receive descriptor
> ring and trashes various chunks of memory that it shouldn't, leading to
> a crash. Given that I never observed this behavior with any of the other
> tulip clones using similar code, I was pretty sure this was a chip bug and
> not some horrible coding error that I had made somewhere.
Yes, I have seen exactly this. I could only get it to happen if I changed
the Winbond's link partner from 10 -> 100 while the Winbond was still in 10.
I see the TDSTAT_Rx_FS and TDSTAT_Rx_LS bits cleared in the descriptor,
as well. When I see this condition occur, I attempt to reset the chip.
This does NOT help this condition on the Winbond. It's thorougly wedged.
Oh yay, cheap chips.
> I saw this with at least three separate Winbond cards and I tried my
> best to detect the condition and smack the chip upside the head to make
> it stop, but I'd be interested to see somebody else duplicate the problem
> and give me their take on it.
Were you ever able to smack it and make it stop? :-)
> Also, just out of curiosity, have you ever observed the PNIC receiver
> bug that gave me so many fits?
I observed it briefly back when there were still some pretty basic bugs
in the driver, which have since been squashed. I haven't seen it since.
I'm aware of the nature of the problem and your work-around. I'm hoping
I don't need to implement it :-)
I have seen some pretty awful problems with the PNIC, tho. The DMA engine
is a piece of crap. On a 500MHz AlphaStation 500, who's PCI bus can surely
keep up with a cheap fast Ethernet board, the PNIC gets constant DMA underruns
unless in Store-and-Forward mode, *including the setup frame*. I have to
initialize the chip into S-F mode just to get the damn filter programmed :-)
I also noticed that DMA underruns don't abort the transmit pipe on the PNIC.
Every DMA underrun on a real packet corresponded to a junk frame hitting
the wire. A short frame I could understand... but we're talking even the
Ethernet header is toast.
Another interesting problem I've been seeing; The very first setup frame
fails to complete. All subsequent setup frames succeed. Including setup
frames sent after an ifconfig down/up. Utterly bizarre.
Oh yay, cheap chips.
...speaking of the PNIC ... I sent you some mail asking where you got
your PNIC manuals... I have been unable to locate any. I haven't even
been able to find the correct contact at Lite-On. Every Lite-On company
I find seems to not have any networking products... *puzzled* Anyhow, just
wondering if you missed that message...
> There's at least one that has a cardbus version... darnit, which is
> is it. Oh: it's the ADMtek. There's an AL982 designed for PCMCIA and
> cardbus use. Unfortunately, the data sheet for it is not on ADMtek's
> server, but it's probably the same core as the AL981. In any case, I
> don't know of any boards that use the AL982. For that matter, I'm not
> even sure which boards use the AL981: the only cards I have are the
> samples that ADMtek sent me, and I haven't seen any board resellers
> claiming to use it.
I'd like to get more info from you about these contacts... I have one each of:
* PNIC board (NetGear variety)
* Macronix board ('15 variety, SOHO)
* Winbond board (Unicom thingie)
...and am looking to get ahold of more in order to get this merged driver
hammered out.
> If you can actually get it all to work and retain some portion of your
> sanity, I'll be mighty impressed.
...you could argue that if I'm even trying at all, I don't have any sanity
to begin with :-)
-- Jason R. Thorpe <thorpej@nas.nasa.gov>
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