ACPICA: Workaround for reversed _PRT entries from BIOS

Some BIOSs erroneously reverse the _PRT SourceName and the
SourceIndex.  Detect and repair this problem. MS ACPI also allows
and repairs this problem, thus ACPICA must also.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/drivers/acpi/resources/rscreate.c b/drivers/acpi/resources/rscreate.c
index faddaee..70c84ec 100644 (file)
--- a/drivers/acpi/resources/rscreate.c
+++ b/drivers/acpi/resources/rscreate.c
@@ -284,6 +284,23 @@ acpi_rs_create_pci_routing_table(union acpi_operand_object *package_object,
                        }
                }
 
+               /*
+                * If the BIOS has erroneously reversed the _PRT source_name (index 2)
+                * and the source_index (index 3), fix it. _PRT is important enough to
+                * workaround this BIOS error. This also provides compatibility with
+                * other ACPI implementations.
+                */
+               obj_desc = sub_object_list[3];
+               if (!obj_desc
+                   || (ACPI_GET_OBJECT_TYPE(obj_desc) != ACPI_TYPE_INTEGER)) {
+                       sub_object_list[3] = sub_object_list[2];
+                       sub_object_list[2] = obj_desc;
+
+                       ACPI_WARNING((AE_INFO,
+                                     "(PRT[%X].Source) SourceName and SourceIndex are reversed, fixed",
+                                     index));
+               }
+
                /*
                 * 3) Third subobject: Dereference the PRT.source_name
                 * The name may be unresolved (slack mode), so allow a null object