[openib-general] [discuss] Re: 2.6.19-rc4: known unfixed regressions (v3)

[Linus Torvalds]

On Wed, 8 Nov 2006, Matthew Wilcox wrote:
>
> On Wed, Nov 08, 2006 at 08:39:44AM +0100, Andi Kleen wrote:
> > ACPI knows the number of busses.
> 
> But what if the number of busses increases later, eg by hotplugging
> a card with a PCI-PCI bridge on it?  Or does it know the number of
> busses which can be supported by this machine's MMCONFIG region?

ACPI will give the maximum number.

However, in this case, the correct thing to do (always _has_ been) is to 
not use ACPI for _anything_, but just read the base and the size of the 
MMCONFIG region from the hardware itself.

Anyway, I do not consider this a regression. MMCONFIG has _never_ worked 
reliably. It has always been a case of "we can make it work on some 
machines by making it break on others".

			Linus