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>

1 files changed, 6 insertions, 16 deletions

diff --git a/drivers/pci/pcie/aer/aerdrv_acpi.c b/drivers/pci/pcie/aer/aerdrv_acpi.c
index f685bf5cdab..8c199ae84f6 100644
--- 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);