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From: Danny Kukawka <danny.kukawka@bisect.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH] smsc95xx: add macaddr module parameter
Date: Tue, 31 Jan 2012 19:17:11 +0100
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On Dienstag, 31. Januar 2012, Alan Cox wrote:
> On Tue, 31 Jan 2012 18:20:33 +0100
>
> Danny Kukawka <danny.kukawka@bisect.de> wrote:
> > Added smsc95xx.macaddr module parameter to allow the user to
> > change the MAC address on boot if there was no MAC on the EEPROM.
>
> NAK. Please see the discussion on this and ifconfig hw for other devices.
>
> In summary - make the device refuse to ifconfig up without a valid
> address, allow it to come into existance without a valid address and then
> use ifconfig.
>
>
> Your patch also seems to break if there are several attached to a board.

There are already other kernel driver which allow to override the (hw) MAC 
address via a module parameter (macaddr): 
- KSZ8841/2 PCI network driver (drivers/net/ethernet/micrel/ksz884x.c)
- FEC Ethernet driver (drivers/net/ethernet/freescale/fec.c)
- Sun HappyMealEthernet(HME) 10/100baseT ethernet driver
  (drivers/net/ethernet/sun/sunhme.c)

By default the MAC from the module parameter get only assigned to the first 
device which got a random MAC (caused by missing EEPROM) before. If you have 
more than one device you can simply assign the MAC to a specific interface 
(e.g. use: macaddr=01:23:45:67:89:ab;eth0). If there are only devices with 
hardware MAC nothing will get changed.

Danny