RE: [PATCH] pci-mmconfig fix for 2.6.9
From: Michael Chan
Date: Fri Nov 12 2004 - 19:11:33 EST
On Fri, 12 Nov 2004, 15:31:59 -0700, Grant Grundler wrote:
> On Fri, Nov 12, 2004 at 01:49:18PM -0800, Michael Chan wrote:
> > In short, I believe mmconfig is allowed to be posted or
> non-posted. If
> > it is posted, there must be a method to allow software to flush it.
> Yes. Agreed.
> But existing direct access methods must implement
> non-postable writes to be compliant.
> E.g. the second paragraph of the Implementation Note:
> | In those cases in which the software must know that a posted
> | transaction is completed by the completer, ...
> IMHO, "In those cases" refers to the second class of systems.
> i386 and x86_64 are (still) in the first class of "legacy" systems.
I think we are almost in agreement. IMHO, the entire ECN applies the
PC-compatible systems and any examples in the Implementation Note is a
valid implementation. mmconfig can be posted, as long as there is a way
to guarantee that the write has completed, such as flush by reading. We
disagree on this point.
The Intel mmconfig implementation is non-posted which is a valid
implementation. Therefore readl is unnecessary and can be removed.
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