setting 100baseTx-FD

[Donald Becker]

On Fri, 12 May 2000, Eric Pop wrote:

> Subject: Re: setting 100baseTx-FD 
> 
> > One of the changes to the v92 (vs. 91g) driver is paying stricter attention
> > to the forced media type flag on the 21143, while still using the EEPROM
> > media table.  I would normally recommend that you try v92, but the best
> > solution is to just not force the media type.
> 
> So... should I give v92 a try?  If the EEPROM is reporting only 10baseT media
> types then that won't do me any good, will it?

Correct.  If the media table doesn't have an entry, you don't know how to
configure the "GP" pins.

> > Ahhh, this might be a problem.  The 21143 media table only has 10baseT
> > types!  The driver *was* doing the best that it could.  Does your card
> > really support 100baseTx?
> 
> Well... that's what it was advertised as.  Though on the other hand I have
> to admit that my machine is one of those Compaq's with everything (e.g sound
> card, video card and ethernet) integrated onto the motherboard.  So I don't
> really know what kind of "card" it is, except for the fact that in Windoze

Was it advertised as 10/100, or only "Ethernet"?  The 21143 needs extra
chips to do 100baseTx, and Compaq might have omitted them from the design.

> > It's possible to force the setting, but the correct solution is to find out
> > why the EEPROM is reporting only 10baseT media types.
> 
> Is there a way I can find out *for sure* if this card really supports 100mbps
> Ethernet?

Yes.
Trace out the design on the motherboard and compare it to the 21143 manual.
That's a lot of work.
If you know what to look for, you could look for the "twister" chip near the
magnetics.
It's easiest for most people to look in the manual for the system.

> If so and if the EEPROM settings are funny -- can I rewrite them
> and still convince the card to operate at 100mpbs-FD?

Yup.  The 'tulip-diag' program (shhhh, don't tell anyone) already has code
to write media tables, and a media table for the Intel CardBus card.
I've written a page on writing media tables at
    http://www.scyld.com/network/tulip-media.html


> Btw, I don't know if this offers any more clues, but as soon as they switched
> my network to 100mpbs capability on Monday morning my connection went down.
> I wasn't able to reestablish it until 48 hours later (doh!) when after many
> trials and error I upgraded the tulip driver to v0.91g (from the original
> v0.89H that came with RedHat6.1).  I wonder what changes between the two 
> driver versions made my network connection possible again?!

The problem was that earlier drivers assumed all 21143 cards could handle
both 10 and 100Mbps, and always advertised 0x01e1.
The updated driver now builds the to-advertise value based on the media
table, specifically to support 21143 cards that don't have all transceiver
types available.

> kernel: tulip.c:v0.91g-ppc 7/16/99 becker@cesdis.gsfc.nasa.gov 
> kernel: eth0: Digital DS21143 Tulip rev 65 at 0x2000, 00:40:D0:0B:40:74, IRQ 
> 10.
> kernel: eth0:  EEPROM default media type Autosense. 
> kernel: eth0:  Index #0 - Media 10baseT (#0) described by a 21142 Serial PHY 
> (2) block.
> kernel: eth0:  Index #1 - Media 10baseT-FD (#4) described by a 21142 Serial 
> PHY (2) block.

Donald Becker				becker@scyld.com
Scyld Computing Corporation
410 Severn Ave. Suite 210
Annapolis MD 21403


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