Re: Netgear FA511 Changes MAC Address

On Wed, 9 Apr 2003, Billy SG McCarthy wrote:

> > Since the driver cannot interpret the EEPROM, it is assuming that this
> > is a multiple port board where the subsequent ports do not have an
> > EEPROM.  The primary fix is to use a driver that has the correct EEPROM
> > interpretation.
> 
> It's not a multiport card, unless I'm misunderstanding what you mean.
> It's only got 1 ethernet jack.

The code in the driver that supports multi-port cards also provides a
fall-back address for cards where the EEPROM cannot be read.

The initial fall-back address is "\040Linux".

To prevent multiple identical MAC addresses, the fall-back address is
incremented each time it is used.

> > Does 'tulip-diag' correctly read the EEPROM information?
> 
> 'tulip-diag' cannot read the EEPROM in either the 2.2 kernel or the
> 2.4.

The tulip-diag program does not depend on the kernel version (beyond
which files in /proc/ it reads to locate the card).

What is the output?


> The 2.2 kernel can somehow figure out the MAC address, while the 2.4
> kernel cannot.

It's not the kernel version, it's the specific driver version.  A driver
version that reads the EEPROM in the 2.2 kernel will also read it
correctly in the 2.4 kernel.

[[ Driver versions need not depend on the kernel version, but somehow
that fact seems to be widely unknown/ignored. ]]

> > Can you eject and re-insert the card, and get the proper MAC address
> > reported in the kernel messages?
> 
> Re-inserting the card gives it a new MAC address.  It starts at
> 00:4C:69:6E:75:79 and increases by 1 each time it is re-insterted, ie
> 00:4C:69:6E:75:7A is the next one.

This is "Linux" -- your EEPROM was not correctly read.

-- 
Donald Becker				[email protected]
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Scyld Beowulf cluster system
Annapolis MD 21403			410-990-9993

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