Re: RFC: Platform data for onboard USB assets

From: Andy Green
Date: Fri Mar 18 2011 - 06:10:20 EST


On 03/18/2011 09:55 AM, Somebody in the thread at some point said:

So how does the Host LAN driver know what MAC address it should use?

This is the problem we're trying to work out. The EEPROM is not
present, and user space has no way of knowing which MAC address
to set to which device. Note that there might be multiple
USB devices of the same type that are indistinguishable to user
space, so setting the MAC address there would not be completely
safe.


And what happens if you need to use u-boot or some bootloader with
ethernet network support?

Wouldn't it be better to have the MAC address programmed at the
bootloader level?

Generally trying to have stuff half done in bootloader and half in Linux makes things fragile and makes another place for trouble to hide (in addition to bootloader state such as U-Boot env or boot.scr or what-have-you needing distro control for updates).

If your bootloader is bloated enough to target network operations under its own steam, it's bloated enough to set a random MAC or use the same CPU ID scheme. But it doesn't mean that Linux should not assert the state it wants when it runs.

-Andy


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