mod for tulip for NetGear FA310TX

Wed Dec 8 23:17:50 1999

Hi folks,

I have been using modified tulip driver for the above-mentioned card for
several days and it appears to have fixed the problem.  No more mysterious

The modified driver was provided to me by William J. Earl, and here's an
excerpt on how it works (according to the mod author):

> > 
> >        Basically, under some circumstances (which might be a combination of
> > half-duplex 10BaseT and some particular PCI bus timing, but which are not clear),
> > some early revisions of the PNIC (Rev. 168 and early Rev. 169) will prefix
> > a small incoming packet with a large amount of garbage data, so that, typically,
> > the resulting packet appears to take up more than one buffer.  Since each
> > buffer is large enough for a legal Ethernet packet, this is appears to be an
> > error.  The driver normally just drops such packets, but, for particular
> > cases, this may mean that most packets of certain types from certain hosts
> > are dropped.  I was seeing dropped ARP replies and TCP ACKs.  
> > 
> >      The workaround is borrowed from the BSD driver.  It enables storing of the
> > CRC in the buffer, clears each buffer before use, and then scans backward
> > in the last buffer of the chain used for the over-long packet for a non-zero
> > byte.  It then uses the correct packet length from the descriptor to find
> > the front of the real packet.  It then discards the garbage in the buffer
> > up to that point, moving the good data to the beginning of a buffer.
> > 

the NIC is recognized as follows by tulip-diag:

Index #1: Found a Lite-On 82c168 PNIC adapter at 0xd000.

The modified tulip module was used with kernel 2.0.38 (x86) successfully,
and I am told that it works with 2.2.x as well.

Besides sharing this info (I understand it was posted previously), I was
hoping to encourage Don and other tulip gods to examine the modified code
so that the fix can be incorporated into the future revision of tulip,
since the card in question is readily available for relatively low price,
at least in my area (SF bay). 

I later found out that NetGear (Bay Network) has published on its web site
its own modified version of tulip driver (based on an earlier release) to
be used with the card.  same plea goes for that as well, though i haven't
used it.