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SubjectRe: [PATCH 2/16 v6] PCI: define PCI resource names in an 'enum'
Bjorn Helgaas wrote:
> On Wednesday 22 October 2008 02:40:41 am Yu Zhao wrote:
>> This patch moves all definitions of the PCI resource names to an 'enum',
>> and also replaces some hard-coded resource variables with symbol
>> names. This change eases introduction of device specific resources.
>
> Thanks for removing a bunch of magic numbers from the code.
>
>> static void
>> pci_restore_bars(struct pci_dev *dev)
>> {
>> - int i, numres;
>> -
>> - switch (dev->hdr_type) {
>> - case PCI_HEADER_TYPE_NORMAL:
>> - numres = 6;
>> - break;
>> - case PCI_HEADER_TYPE_BRIDGE:
>> - numres = 2;
>> - break;
>> - case PCI_HEADER_TYPE_CARDBUS:
>> - numres = 1;
>> - break;
>> - default:
>> - /* Should never get here, but just in case... */
>> - return;
>> - }
>> + int i;
>>
>> - for (i = 0; i < numres; i++)
>> + for (i = 0; i < PCI_BRIDGE_RESOURCES; i++)
>> pci_update_resource(dev, i);
>> }
>
> The behavior of this function used to depend on dev->hdr_type. Now
> we don't look at hdr_type at all, so we do the same thing for all
> devices.
>
> For example, for a CardBus device, we used to call pci_update_resource()
> only for BAR 0; now we call it for BARs 0-6.
>
> Maybe this is safe, but I can't tell from the patch, so I think you
> should explain *why* it's safe in the changelog.

It's safe because pci_update_resource() will ignore unused resources.
E.g., for a Cardbus, only BAR 0 is used and its 'flags' is set, then
pci_update_resource() only updates it. BAR 1-6 are ignored since their
'flags' are 0.

I'll put more explanation in the changelog.

Thanks,
Yu


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