Re: Avoid creating P2P prefetch window for expansion ROMs

A kernel without the patch always forced creation of a prefetch
window for expansion ROMs which was incorrect on systems where
insufficient memory resources are available for both non-prefetch
and prefetch windows. On the systems I was dealing with, the
BIOS assumes (correctly, I believe) that expansion ROM memory
resource needs will be satisfied from the non-prefetch window.

Why would ROM space generally need to be non-prefetchable? I can
see that special cases might require this, but as long as ROM space
really is just normal code and data, there's nothing wrong with
prefetching from it I would think. Of course I realize there's no way
to specify that on a per-device basis, so I think the BIOS must be
relied upon here.

I think it would still be useful to know what system/PCI adapter
combination you are seeing the problem with so that I can try
to put together a setup that will reproduce the problem here.
Alternatively, it would good if you wouldn't mind providing
more information, testing possible fixes, etc. As a start,
could you send me the following taken with and without the
patch?
- /proc/iomem
- /proc/ioports
- `dmesg` output
- `lspci -vt` output
- `lspci -vvv` output

Attached. *.0 is with the patch, *.1 is with it reverted. All output from
the SLE10SP2 (2.6.16.54-based) kernel that has that patch backported.

I'd also like to note that I found that a second of the systems I'm
regularly dealing with also has similar problems. I'm just not normally
looking at the boot messages that closely.

Jan

Attachment: lspci-vvv.1
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Attachment: dmesg.1
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Attachment: iomem.0
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Attachment: iomem.1
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Attachment: ioports.0
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Attachment: ioports.1
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Attachment: lspci-vt.0
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Attachment: lspci-vt.1
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Attachment: lspci-vvv.0
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Attachment: dmesg.0
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