Subject: Re: [PATCH] powerpc: fix MAC address entries for 83xx, 85xx, and 86xx device trees

From: Timur Tabi <[email-masked]>
Date: Mon, 25 Jun 2007 11:01:41 -0500

Segher Boessenkool wrote:

> Yup, they're both marked for removal so let's just remove them
> at the same time.

As soon as Paul creates a "for-2.6.25" branch, that's when I was planning on doing it.

> Does the kernel provide a warning to users of too-old firmware^Wuboot
> telling them to update btw?

Nope.  The current U-Boot code updates mac-address and/or local-mac-address, whichever 
ones exist.  If neither exists, it doesn't do anything.  If both exists, it updates both 
with the same value.  This makes it DTS-agnostic, so to speak.

The kernel looks at each of the properties and uses the first one that has a valid MAC 
address.  Again, this is U-Boot- and DTS-agnostic.

Some older U-Boots would panic if the property it looks for didn't exist.  Some Linux 
drivers would simply not find a MAC address and then fail to load.

In other words, the current U-Boot and Linux code is written to not care what the other 
one does.  I have no plans to remove the code in the kernel that looks for obsolete 
entries (I'm talking about function of_get_mac_address), because it's "safe".

However, now that you mention it, I could update function of_get_mac_address() to display 
a warning if it only finds the 'address' property.  That property is definitely wrong and 
should never be in the DTS or any device tree passed to the kernel.

-- 
Timur Tabi
Linux Kernel Developer @ Freescale