Re: [PATCH 2/2] PCI, ACPI, x86: update MMCFG information whenhot-plugging PCI host bridges

From: Yinghai Lu
Date: Tue Apr 10 2012 - 11:47:27 EST


On Tue, Apr 10, 2012 at 3:32 AM, Kenji Kaneshige
<kaneshige.kenji@xxxxxxxxxxxxxx> wrote:
> Additionally, I think there is a remaining issue even if we change
> this check like below.
>
>
>        if (!!(pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF))
>                return 0;
>
> I think this check has an assumption that system has at least one
> MCFG table entry and it has been initialized before
> acpi_pci_root_add() is called. I think this doesn't work on the
> system that doesn't have MCFG and all the pci root bridge have
> _CBA (that is, all host bridges are hot-pluggable and BIOS is
> implemented in the way PCI FW spec defines). As a result, MMCONFIG
> would never be enabled on such systems. Could you double check this?

You are right.

We can just remove that checking.

But wonder if current x86_64 system support that.
All peer root buses can be physically removed ?

Thanks

Yinghai
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