Re: [PATCH 0/7][RESEND] acpi, pci: hostbridge hotplug support

[Jiang Liu <liuj97@gmail.com>]

On 09/01/2012 12:44 AM, Yinghai Lu wrote:
> On Thu, Aug 30, 2012 at 10:42 PM, Bjorn Helgaas <bhelgaas@google.com> wrote:
>>
>> That's true.  I think we should blindly probe for devices only when
>> (1) the system does not have ACPI or (2) the DMI BIOS date is older
>> than some date, e.g., 1 Jan 2013.  For new systems with ACPI, we
>> should only look at the host bridges described in ACPI.
> 
> if those buses do not get scanned, then it should be enough.
> 
> how about just removing pcibios_last_bus probing code?
> 
> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
> index 937bcec..3f3c460 100644
> --- a/arch/x86/pci/mmconfig-shared.c
> +++ b/arch/x86/pci/mmconfig-shared.c
> @@ -616,16 +616,6 @@ static void __init __pci_mmcfg_init(int early)
>         if (list_empty(&pci_mmcfg_list))
>                 return;
> 
> -       if (pcibios_last_bus < 0) {
> -               const struct pci_mmcfg_region *cfg;
> -
> -               list_for_each_entry(cfg, &pci_mmcfg_list, list) {
> -                       if (cfg->segment)
> -                               break;
> -                       pcibios_last_bus = cfg->end_bus;
> -               }
> -       }
> -
>         if (pci_mmcfg_arch_init())
>                 pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
>         else {
> 
> 
> also Nehalem *EX* and Westmere *EX* does not support EDAC.
> 
> so if the user with Nehalem/Westmere Desktop version, want to use to
> EDAC, they could just append
> pci=last_bus=255 to get those buses scanned.
I think this is a better solution than non-ACPI root bus hotplug.
--Gerry