PCI: Run ACPI _OSC method on root bridges only

According to the PCI Firmware Specification Revision 3.0 section 4.5, _OSC
should only be called on a root brdige.  Here is the relevant passage: "The
_OSC interface defined in this section applies only to Host Bridge ACPI
devices that originate PCI, PCI-X, or PCI Express hierarchies". Changed the
code to find the parent root bridge of the device and call _OSC on that.

Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/pcie/aer/aerdrv_acpi.c b/drivers/pci/pcie/aer/aerdrv_acpi.c
index f685bf5..8c199ae 100644 (file)
--- a/drivers/pci/pcie/aer/aerdrv_acpi.c
+++ b/drivers/pci/pcie/aer/aerdrv_acpi.c
@@ -31,23 +31,13 @@ int aer_osc_setup(struct pcie_device *pciedev)
 {
        acpi_status status = AE_NOT_FOUND;
        struct pci_dev *pdev = pciedev->port;
-       acpi_handle handle = DEVICE_ACPI_HANDLE(&pdev->dev);
-       struct pci_bus *parent;
+       acpi_handle handle = 0;
 
-       while (!handle) {
-               if (!pdev || !pdev->bus->parent)
-                       break;
-               parent = pdev->bus->parent;
-               if (!parent->self)
-                       /* Parent must be a host bridge */
-                       handle = acpi_get_pci_rootbridge_handle(
-                                       pci_domain_nr(parent),
-                                       parent->number);
-               else
-                       handle = DEVICE_ACPI_HANDLE(
-                                       &(parent->self->dev));
-               pdev = parent->self;
-       }
+       /* Find root host bridge */
+       while (pdev->bus && pdev->bus->self)
+               pdev = pdev->bus->self;
+       handle = acpi_get_pci_rootbridge_handle(
+               pci_domain_nr(pdev->bus), pdev->bus->number);
 
        if (handle) {
                pcie_osc_support_set(OSC_EXT_PCI_CONFIG_SUPPORT);