[PATCH 4/4] PCI: Run ACPI _OSC method on root bridges only

Andrew Patterson
2008-01-23T00:18:29Z

From: Andrew Patterson <andrew.patterson@hp.com>

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>
---

drivers/pci/pcie/aer/aerdrv_acpi.c | 22 ++++++----------------
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 f685bf5..8c199ae 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);