Re: [PATCH 1/2] pci, msi: Remove unused/obsolete macros and definitions

From: Matthew Wilcox
Date: Mon Apr 20 2009 - 07:06:50 EST


On Mon, Apr 20, 2009 at 10:54:52AM +0900, Hidetoshi Seto wrote:
> - Remove unused msi/msix_enable/disable macros.
> User should use msi/msix_set_enable() functions instead.

I don't think they were ever intended for drivers; I think they were
supposed to be helper macros for msi.c. Regardless, deleting them is
the right thing to do.

> - Remove unused msix_mask/unmask/pending macros.
> These macros are useless because they are not based on any of
> the PCI Local Bus Specifications properly.
> It seems that they were written based on a draft of PCI spec,
> and that the draft was the MSI-X ECN that underwent membership
> review in September 2002.
> (* In the draft, the size of a entry in MSI-X table was 64bit,
> containing 32bit message data and DWORD aligned lower address
> plus a pending bit and a mask bit.(30+1+1bit) The higher
> address was placed in MSI-X capability structure and shared
> by all entries.)

I think you're right. Unfortunately, the old MSI-X ECN was actually
incorporated into a version of the PCI 3.0 spec -- I have a document
here named pci3.0-081202.pdf which has exactly the layout you describe.
So it probably gained wider currency than it should have.

> - Remove PCI_MSIX_FLAGS_BITMASK.
> This definition also come from the draft ECN.

Yep.

> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>

Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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