Re: [PATCH v8 06/12] PCI/ACPI: provide MCFG address for PCI host bridges

[Jiang Liu <jiang.liu@huawei.com>]

Hi Yinghai,
> thought you were agreeing to go through choice 2 without caching MCFG anymore.
> 
> Can you just drop that caching MCFG and only handle _CBA here?
> 
> Thanks
> 
> Yinghai

	Yes, I'm going to adopt solution two as you suggested. 
On the other hand, the MMCFG caching is kept due to following
considerations:
1) To emit a warning message if MMCFG entries in MCFG table only
partially covers buses under a PCI host bridge. Taku reported that
he has a system which exhibits such a behavior.
2) To cross-check that MMCFG addresses returned by MCFG table and 
_CBA method are consistent if both are available (though that 
violates the PCI FW/ACPI specifications).
3) In future, we may try to remove MMCFG entry constructed from
MCFG table when hot-removing a PCI host bridge. We have some systems
which assign a distinguish segment ID for each host bridge. In such
a case, it may be reasonable to remove the MMCFG entry when removing
a host bridge.
4) The MCFG cache should be small under normal cases.

	If you feel it's unnecessary to keep the cache, I will remove
it and send out a updated version soon.
	Thanks!
	Gerry