pci: clear osc support flags if no _OSC method

So it looks like pci aer code will call pci_osc_support_set to tell the
firmware about  OSC_EXT_PCI_CONFIG_SUPPORT flag.  that causes
ctrlset_buf[OSC_SUPPORT_TYPE] to evaluate to true when pciehp calls
pci_osc_control_set() is called (to attempt to use OSC to gain native
pcie control from firmware), regardless of whether or not _OSC was
actually successfully executed.  That causes this section of code:
 if (ctrlset_buf[OSC_SUPPORT_TYPE] &&
                ((global_ctrlsets & ctrlset) != ctrlset)) {
                return AE_SUPPORT;
        }
to be hit.

This patch will reset the OSC_SUPPORT_TYPE field if _OSC fails, and then
would allow pciehp to go ahead and try to run _OSC again.

Signed-off-by:  Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index bb7456c1dbac..a064f36a0805 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -36,6 +36,7 @@ acpi_query_osc (
         struct acpi_buffer      output = {ACPI_ALLOCATE_BUFFER, NULL};
         union acpi_object       *out_obj;
         u32                     osc_dw0;
+        acpi_status *ret_status = (acpi_status *)retval;
 
         
         /* Setting up input parameters */
@@ -56,6 +57,7 @@ acpi_query_osc (
         if (ACPI_FAILURE (status)) {
                 printk(KERN_DEBUG  
                         "Evaluate _OSC Set fails. Status = 0x%04x\n", status);
+                *ret_status = status;
                 return status;
         }
         out_obj = output.pointer;
@@ -90,6 +92,7 @@ acpi_query_osc (
 
 query_osc_out:
         kfree(output.pointer);
+        *ret_status = status;
         return status;
 }
 
@@ -166,6 +169,7 @@ run_osc_out:
 acpi_status pci_osc_support_set(u32 flags)
 {
         u32 temp;
+        acpi_status retval;
 
         if (!(flags & OSC_SUPPORT_MASKS)) {
                 return AE_TYPE;
@@ -179,9 +183,13 @@ acpi_status pci_osc_support_set(u32 flags)
         acpi_get_devices ( PCI_ROOT_HID_STRING,
                         acpi_query_osc,
                         ctrlset_buf,
-                        NULL );
+                        (void **) &retval );
         ctrlset_buf[OSC_QUERY_TYPE] = !OSC_QUERY_ENABLE;
         ctrlset_buf[OSC_CONTROL_TYPE] = temp;
+        if (ACPI_FAILURE(retval)) {
+                /* no osc support at all */
+                ctrlset_buf[OSC_SUPPORT_TYPE] = 0;
+        }
         return AE_OK;
 }
 EXPORT_SYMBOL(pci_osc_support_set);