[coreboot] Subtractive Resources

ron minnich rminnich at gmail.com
Fri Nov 7 17:54:40 CET 2008

On Fri, Nov 7, 2008 at 8:46 AM, Myles Watson <mylesgw at gmail.com> wrote:

> My understanding is that the amd8111 _has_ a bridge, but the device that is
> causing the problem is lpc, which is not a bridge, nor behind the amd8111's
> bridge.  So when its resources are read and it is found to have subtractive
> resources, the code tries to descend.  It doesn't have a bus, and this
> fails.

you are right. I missed it. That's a good catch.

Do you need those resources added for correct operation?

Even if we had a link, does it make sense to descend the link to read
subtractive resources?

I like patch 1 but at the same time it feels like maybe we're not
getting at the right problem. If we're that point in the code, and
reading links, why are the links not there?

> Sorry I wasn't more clear.  I meant that the fix no longer tries to call
> functions with NULL pointers.  I don't think the dts is wrong, but I think
> that there are a lot fewer intermediaries in v3 then there were in v2.

Well, that I  like to hear.

Marc made the case that things such as superio should not even be
"under" the lpc in the dts, since they stand "outside" the tree in
some sense. He argued that we should instead put them at top level.
There is merit to his argument. This would simplify the lpc code as

Still, this is starting to converge to a more sensible block of code.


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