Re: [bug] e100 bug: checksum mismatch on 82551ER rev10

[Auke Kok <auke-jan.h.kok@intel.com>]

Molle Bestefich wrote:
> Auke Kok wrote:
> > > Every single IP130 I've had my hands on has had an EEPROM that the
> > > Linux driver declared bad.
> >
> > that means that whoever is selling you the IP130's is consistently 
> > putting on
> > bad EEPROMs, which is *very* bad. Which vendor is that? They can fix this
> > problem for you and for *everyone* else they have sold and will sell 
> > IP130's
> > to in the future.
>
> Nokia.
>
> Maybe they've changed the BABA magic, or the checksum logic entirely,
> to prevent other software than their own OS from running.

in almost all cases where a bad EEPROM checksum is found on a board the vendor 
has changed settings in the EEPROM image without recalculating the checksum.

> > > I'm afraid that it's not the board that's at fault, it's the driver.
> >
> > No it is not. The NIC is supported (you can even call Intel for first 
> > line
> > support) but if your vendor put a bad EEPROM image on it then all bets 
> > are
> > off.  Intel provides the vendors with the proper tools to make valid 
> > EEPROMs,
> > the driver checks them for a very good reason.
>
> You're completely sure that the EEPROM check is correct for this
> particular revision of this particular chip?

It's valid for every piece of network silicon that has an EEPROM ever made.

> (Do you happen to know where the EEPROM is located, by the way?

it's in the NIC itself. In your case, where you have 3 separate chips, there 
will be 3 different EEPROM images total.

> > How can you tell? Do you know if jumbo frames work correctly?  Is the 
> > device
> > properly checksumming? is flow control working properly?  These and 
> > many, many
> > more settings are determined by the EEPROM.  Seemingly it may work 
> > correctly,
> > but there is no guarantee whatsoever that it will work correctly at 
> > all if the
> > checksum is bad.  Again, you can lose data, or worse, you could 
> > corrupt memory
> > in the system causing massive failure (DMA timings, etc). Unlikely? 
> > sure, but
> > not impossible.
>
> They've been used in production environments for years.

all the more reason to suggest that Nokia is forgetting to update the checksums :)

Cheers,

Auke
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