Subject: Re: removing get_immrbase()??

From: Timur Tabi <[email-masked]>
Date: Thu, 23 Apr 2009 09:02:49 -0500

Anton Vorontsov wrote:

> And note that most developers are using up-to-date firmwares
> (U-Boots), device trees, and kernels. 

Developers? Yes.
End-users? No.

Updating U-Boot itself is often unacceptable for end-users.  There's
also a strong connection between U-Boot and the device tree.  That
connection gets stronger with every release, as U-Boot makes more and
more changes to the device tree before passing it to the kernel.  This
means that if you cannot update U-Boot, you might not be able to update
your device tree either.

We've run into plenty of situations where customers will update the
kernel, but insist that U-Boot and the device tree remain unchanged.

> And that means that old
> device-tree + new kernel combination is left untested for years.
> And untested stuff is broken stuff, by definition.

I'm not saying that should officially support it.  I'm saying we should
make an effort to minimize the problem.  Adding a few isolated lines of
code to maintain that compatibility, and running a few tests, is not a
bad idea and can save headaches for some people in the future.

-- 
Timur Tabi
Linux kernel developer at Freescale