ACPI / PCI: pci_link: Allow the absence of _PRS and change log level

BugLink: https://bugs.launchpad.net/bugs/1773295
In recent Intel hardware the IRQs become non-configurable after BIOS
initializes them in PEI phase and _PRS objects are no longer included in
ASL.

This is the same as "static (non-configurable) devices do not
specify a _PRS object" in ACPI spec. As a result, error messages
saying "ACPI Exception: AE_NOT_FOUND, Evaluating _PRS" does not need to
be in kernel messenges all the time but only when debug is enabled, and
acpi_pci_link_get_possible should not return -ENODEV when _PRS is
absent.

Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 92d1b381f677cbd2d4370dc3b8d0679b7f0ace32)
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Acked-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index bc3d914dfc3e397880581b56b33188f575ea160d..65f1908480d4716f7c01197892a658ef38570543 100644 (file)
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -173,8 +173,8 @@ static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
        status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
                                     acpi_pci_link_check_possible, link);
        if (ACPI_FAILURE(status)) {
-               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
-               return -ENODEV;
+               acpi_handle_debug(link->device->handle, "_PRS not present or invalid");
+               return 0;
        }
 
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,