On Fri, 07 Jan 2011 21:44:35 +0100
Jiri Slaby [off-list ref] wrote:

On 01/06/2011 08:24 PM, Bjorn Helgaas wrote:

quoted

Theoretically, ACPI tells us about the GPIO/TCO/etc. regions in a
generic way via namespace devices or something in the static tables.
Is that generic information missing, or is it there and Linux is
ignoring it?  If we're ignoring it, I'd rather fix that.

It works for most boxes I would say. Try to google for "claimed by ICH4
ACPI/GPIO/TCO", it reports sane ranges like 0400-047f or 4000-407f.

quoted

The main reason for claiming I/O regions is to keep us from placing
another device on top of them.  But we've had PCIBIOS_MIN_IO = 0x1000
forever, which should keep us from putting anything below that anyway
(at least for PCI devices).  So there must be some other reason for
claiming space in this quirk.

Anyway, this ACPI space may be below 0x1000 as can be seen above. From
the ICH standard, it can be anywhere...

Is there some other resource we should be considering to avoid this
space?

And we know it won't work if we try to use the IDE controller in the
LPC allocated space?  Have you checked the ICH4 specs to see what the
decode rules are on this space?  I guess LPC has priority and doesn't
forward requests through to IDE?

Either way, it would be good to understand this issue a little better
before we start restricting the LPC space like this.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center