ACPI: fix boot hang w/o "noapic" on MSI MS-6390-L

This is a workaround to handle a BIOS bug where the
programmer exchanged the name and index fields of
a _PRT entry.  Apparently this BIOS error does not
confuse Windows and thus it lurks in the field
on various machines.

boot with "acpi=strict" to disable this workaround

http://bugzilla.kernel.org/show_bug.cgi?id=6859

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 23 insertions, 2 deletions

diff --git a/drivers/acpi/resources/rscreate.c b/drivers/acpi/resources/rscreate.c
index 1358c06a969c..cc48ab05676c 100644
--- a/drivers/acpi/resources/rscreate.c
+++ b/drivers/acpi/resources/rscreate.c
@@ -191,6 +191,9 @@ acpi_rs_create_pci_routing_table(union acpi_operand_object *package_object,
         user_prt = ACPI_CAST_PTR(struct acpi_pci_routing_table, buffer);
 
         for (index = 0; index < number_of_elements; index++) {
+                int source_name_index = 2;
+                int source_index_index = 3;
+
                 /*
                  * Point user_prt past this current structure
                  *
@@ -261,10 +264,28 @@ acpi_rs_create_pci_routing_table(union acpi_operand_object *package_object,
                 }
 
                 /*
+                 * If BIOS erroneously reversed the _PRT source_name and source_index,
+                 * then reverse them back.
+                 */
+                if (ACPI_GET_OBJECT_TYPE (sub_object_list[3]) != ACPI_TYPE_INTEGER) {
+                        if (acpi_gbl_enable_interpreter_slack) {
+                                source_name_index = 3;
+                                source_index_index = 2;
+                                printk(KERN_WARNING "ACPI: Handling Garbled _PRT entry\n");
+                        } else {
+                                ACPI_ERROR((AE_INFO,
+                                        "(PRT[%X].source_index) Need Integer, found %s",
+                                        index,
+                                        acpi_ut_get_object_type_name(sub_object_list[3])));
+                                return_ACPI_STATUS(AE_BAD_DATA);
+                        }
+                }
+
+                /*
                  * 3) Third subobject: Dereference the PRT.source_name
                  * The name may be unresolved (slack mode), so allow a null object
                  */
-                obj_desc = sub_object_list[2];
+                obj_desc = sub_object_list[source_name_index];
                 if (obj_desc) {
                         switch (ACPI_GET_OBJECT_TYPE(obj_desc)) {
                         case ACPI_TYPE_LOCAL_REFERENCE:
@@ -339,7 +360,7 @@ acpi_rs_create_pci_routing_table(union acpi_operand_object *package_object,
 
                 /* 4) Fourth subobject: Dereference the PRT.source_index */
 
-                obj_desc = sub_object_list[3];
+                obj_desc = sub_object_list[source_index_index];
                 if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_INTEGER) {
                         user_prt->source_index = (u32) obj_desc->integer.value;
                 } else {