[vortex] two models of 3C905C-TX-M and transfert error with 3C905C-TX-M

[Bogdan Costescu]

On Wed, 11 Oct 2000, Olivier.Guibe wrote:

> I had the same problem of Sergei Klioner (see the bug-mailing list),

The ideea of that thread was that the main memory could have caused data
corruption. In your case, you put the card in another computer and got
the same results, so it's not the same problem.

> If I put the 3Com of the good one on the bad one, ftp and Netscape
> are perfect. So one 3Com is perfect and the other one not.
> I got another (bad) 3Com network card.

There might be hardware problems. But before jumping to this conclusion
(which probably implies that you have to change the cards):
- what kernel and 3c59x driver version are you using ?
- what is the output of vortex-diag (from
http://www.scyld.com/network/vortex.html) for a" good" and a "bad" card ?
- are you sure that you don't have any memory-related or PCI related
problems on both computers ? (e.g. overclocking might produce them)

> In fact there is a difference between the two cards.
> On the good card, a chip is written 'BEL' (and a different word on the
> other one).

I think that the chip with 'BEL' on it has nothing to do with data
corruption. I'm not hardware expert, but I think that it only handles
signals between the main chip and the wires. If this chip would produce
any glitch, it would be caught by the main chip through CRC. The only data
corruption that could go "unnoticed" is between the main chip, PCI bus and
main memory when on-board checksumming facilities are used, as explained
in the earlier mentioned thread; also in this thread, Don Becker suggests
modifying one line in the driver's source code to disable hardware
checksumming. Could you try to do this ? (I am, as Don previously, 
skeptical about the results).

-- 
Bogdan Costescu

IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen
Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY
Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868
E-mail: Bogdan.Costescu@IWR.Uni-Heidelberg.De