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>

diff --git a/drivers/acpi/resources/rscreate.c b/drivers/acpi/resources/rscreate.c
index 1358c06..cc48ab0 100644 (file)
--- 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 {