[U-Boot] DM9000 : MAC Address mismatch with Linux kernel

[Wolfgang Denk]

Dear Stefano,

In message <4A2F7183.2000407 at denx.de> you wrote:
> 
> This generates a strange phenomen:
> 
> 1. The target works in u-boot with a mac address, and with this address
> for example loads the kernel from network.
> 
> 2. When the kernel boots, the system takes a different mac address,
> because the mac address passed by u-boot is not used.

I understand this is on an ARM system - but  there  U-Boot  does  not
pass any MAC address information to the kernel - at least there is no
standard  way  for  doing  this.  So  either  you  don't pass any MAC
information to Linux, and Linux does the best  effort,  or  you  have
defined  your  own method (like using an "ethadd=" boot argument like
some others do), but you failed to adapt the driver to  pick  up  the
information from there.

In both cases you have no real reason to complain :-)

[But I understand that you are dissatisfied with the current
behaviour.]

> IMHO we should synchronize the two values, writing down the Eeprom in
> the case the ethaddr is set. I think this is congruent with all other

See my posting from yesterday - 
http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/54542/focus=61202

I agree that if we have two different  values,  there  should  be  at
least a warning printed by U-Boot.

> boards in u-boot (ethaddr has the highest priority).

I also agree that the "ethaddr" setting should have higher priority.

I am not so sure however if we should automatically change the MAC
address in the EEPROM of the network adapter - I don't think this is a
really good idea.

> However, I do not know if this behavior is always acceptable (for
> example, if the mac address is written in the factory and the component
> has a label reporting the mac address) and it is not so easy to find in
> u-boot which boards with the DM9000 controller have a serial eeprom
> attached to it.
> 
> Any opinion about it ?

My vote is to re-add the warning message that got dropped in the above
mentioned series of patches, and provide means to the user to manually
sync the addresses - one way or the other, dependent on user's
discretion.

Best regards,

Wolfgang Denk

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