ACPI: ACPICA 20060217

Implemented a change to the IndexField support to match
the behavior of the Microsoft AML interpreter. The value
written to the Index register is now a byte offset,
no longer an index based upon the width of the Data
register. This should fix IndexField problems seen on
some machines where the Data register is not exactly one
byte wide. The ACPI specification will be clarified on
this point.

Fixed a problem where several resource descriptor
types could overrun the internal descriptor buffer due
to size miscalculation: VendorShort, VendorLong, and
Interrupt. This was noticed on IA64 machines, but could
affect all platforms.

Fixed a problem where individual resource descriptors were
misaligned within the internal buffer, causing alignment
faults on IA64 platforms.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/acpi/executer/exprep.c b/drivers/acpi/executer/exprep.c
index 7719ae5d4f16..916234bf811c 100644
--- a/drivers/acpi/executer/exprep.c
+++ b/drivers/acpi/executer/exprep.c
@@ -519,13 +519,20 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
                 acpi_ut_add_reference(obj_desc->index_field.index_obj);
 
                 /*
+                 * February 2006: Changed to match MS behavior
+                 *
                  * The value written to the Index register is the byte offset of the
-                 * target field
-                 * Note: may change code to: ACPI_DIV_8 (Info->field_bit_position)
+                 * target field.
+                 *
+                 * Previously, the value was calculated as an index in terms of the
+                 * width of the Data register, as below:
+                 *
+                 *   obj_desc->index_field.Value = (u32)
+                 *       (Info->field_bit_position / ACPI_MUL_8 (
+                 *           obj_desc->Field.access_byte_width));
                  */
-                obj_desc->index_field.value = (u32)
-                    (info->field_bit_position /
-                     ACPI_MUL_8(obj_desc->field.access_byte_width));
+                obj_desc->index_field.value =
+                    (u32) ACPI_DIV_8(info->field_bit_position);
 
                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                   "index_field: bit_off %X, Off %X, Value %X, Gran %X, Index %p, Data %p\n",