On Wed, Nov 5, 2014 at 1:57 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>
> It's relatively common to start with a pci_dev and look for an ACPI handle
> that corresponds to that device or the closest enclosing scope, so maybe
> there should be a way to do that directly.
>
> For pci_get_hp_params(), I think the current code is actually slightly
> buggy because we don't look for _HPP/_HPX on the device itself; we only
> look at the bridges upstream from it.
>
> What I had in mind was something like the following (untested and not for
> application).
> + * Search for an ACPI handle. The PCI device itself may have one, or an
> + * upstream device (either a PCI-to-PCI bridge or a PCI host bridge) may
> + * have one.
> + */
> +acpi_handle pci_find_acpi_handle(struct pci_dev *pdev)
> +{
> + struct device *dev;
> + acpi_handle handle;
> + struct pci_bus *bus;
> +
> + dev = &pdev->dev;
> + handle = ACPI_HANDLE(dev);
> + while (!handle) {
> + pdev = pci_physfn(pdev);
I'm a little worried about to apply hpx value for PFs to VFs.
> + bus = pdev->bus;
> + if (pci_is_root_bus(bus))
> + dev = bus->bridge;
> + else {
> + pdev = bus->self;
> + dev = &pdev->dev;
> + }
> + handle = ACPI_HANDLE(dev);
> + }
> + return handle;
> +}
Also found another problem,
pci_device_add==>pci_configure_device==>program_hpp_type2() path.
and program_hpp_type2() will check dev->subordinate().
but at the time child bridge is not scanned yet.
Maybe we should move pci_configure_device later ?
Yinghai Lu
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