ACPI / PCI: Do not try to acquire _OSC control if that is hopeless

If acpi_pci_osc_support() fails for the given flags, it doesn't make
sense to call acpi_pci_osc_control_set() down the road for the same
flags, because it will certainly fail too.  Moreover, problem
diagnostics is then harder, because it is not too easy to identify
the reason of the _OSC failure in those cases.

For this reason, check the status returned by acpi_pci_osc_support()
for PCIe support flags and do not attempt to execute
acpi_pci_osc_control_set() for those flags and print a message if
it's "failure".  For compatibility with the existing code, disable
ASPM in that case too.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7aff6312ce7c75a66d731b5ea0a10743e7b34c5f..c86b392174001a7047d0a9155f0b5e6ad2723bff 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -571,8 +571,15 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
                        OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
        if (pci_msi_enabled())
                flags |= OSC_MSI_SUPPORT;
-       if (flags != base_flags)
-               acpi_pci_osc_support(root, flags);
+       if (flags != base_flags) {
+               status = acpi_pci_osc_support(root, flags);
+               if (ACPI_FAILURE(status)) {
+                       dev_info(root->bus->bridge, "ACPI _OSC support "
+                               "notification failed, disabling PCIe ASPM\n");
+                       pcie_no_aspm();
+                       flags = base_flags;
+               }
+       }
 
        if (!pcie_ports_disabled
            && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {