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

From: Auke Kok
Date: Mon Jul 10 2006 - 14:01:57 EST


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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