Ingo Molnar wrote:
> * Han, Weidong <weidong.han@xxxxxxxxx> wrote:
>
>> Siddha, Suresh B wrote:
>>> On Wed, 2009-05-06 at 23:16 -0700, Han, Weidong wrote:
>>>> @@ -634,6 +694,44 @@ static int ir_parse_ioapic_scope(struct
>>>> acpi_dmar_header *header, " 0x%Lx\n",
>>>> scope->enumeration_id, drhd->address);
>>>>
>>>> + bus = pci_find_bus(drhd->segment, scope->bus);
>>>> + path = (struct acpi_dmar_pci_path *)(scope + 1); + count =
>>>> (scope->length - + sizeof(struct acpi_dmar_device_scope))
>>>> + / sizeof(struct acpi_dmar_pci_path);
>>>> +
>>>> + while (count) {
>>>> + if (pdev)
>>>> + pci_dev_put(pdev);
>>>> +
>>>> + if (!bus)
>>>> + break;
>>>> +
>>>> + pdev = pci_get_slot(bus,
>>>> + PCI_DEVFN(path->dev, path->fn));
>>>> + if (!pdev)
>>>> + break;
>>>
>>> ir_parse_ioapic_scope() happens very early in the boot. So, I
>>> don't think we can do the pci related discovery here.
>>>
>>
>> Thanks for your pointing it out. It should enable the source-id
>> checking for io-apic's after the pci subsystem is up. I will
>> change it.
>
> Note, there's ways to do early PCI quirks too, check
> arch/x86/kernel/early-quirks.c. It's done by reading the PCI
> configuration space directly via a careful early-capable subset of
> the PCI config space APIs.
>
> But it's a method of last resort.
>
Thanks for your reminder. It can use direct PCI access here as follows. It's easy and clean. I think it's better than adding the source-id checking for io-apic's after the pci subsystem is up. I will send out updated patches after some tests.
@@ -634,6 +695,24 @@ static int ir_parse_ioapic_scope(struct acpi_dmar_header *header,
" 0x%Lx\n", scope->enumeration_id,
drhd->address);
+ bus = scope->bus;
+ path = (struct acpi_dmar_pci_path *)(scope + 1);
+ count = (scope->length -
+ sizeof(struct acpi_dmar_device_scope))
+ / sizeof(struct acpi_dmar_pci_path);
+
+ while (--count > 0) {
+ /* Access PCI directly due to the PCI
+ * subsystem isn't initialized yet.
+ */
+ bus = read_pci_config_byte(bus, path->dev,
+ path->fn, PCI_SECONDARY_BUS);
+ path++;
+ }
+
+ ir_ioapic[ir_ioapic_num].bus = bus;
+ ir_ioapic[ir_ioapic_num].devfn =
+ PCI_DEVFN(path->dev, path->fn);
ir_ioapic[ir_ioapic_num].iommu = iommu;
ir_ioapic[ir_ioapic_num].id = scope->enumeration_id;
ir_ioapic_num++;
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