ACPICA: Add repair for predefined methods that return nested packages

Fixes a problem where a predefined method is defined to return
a variable-length Package of sub-packages. If the length is one,
the BIOS code occasionally creates a simple single package with
no sub-packages. This code attempts to fix the problem by wrapping
a new package object around the existing package. ACPICA BZ 790.

http://acpica.org/bugzilla/show_bug.cgi?id=790

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>

3 files changed, 84 insertions, 2 deletions

diff --git a/drivers/acpi/acpica/acnamesp.h b/drivers/acpi/acpica/acnamesp.h
index 908cfdd3b895..f75a7a01b875 100644
--- a/drivers/acpi/acpica/acnamesp.h
+++ b/drivers/acpi/acpica/acnamesp.h
@@ -278,6 +278,10 @@ acpi_ns_repair_object(struct acpi_predefined_data *data,
                       u32 package_index,
                       union acpi_operand_object **return_object_ptr);
 
+acpi_status
+acpi_ns_repair_package_list(struct acpi_predefined_data *data,
+                            union acpi_operand_object **obj_desc_ptr);
+
 /*
  * nssearch - Namespace searching and entry
  */
diff --git a/drivers/acpi/acpica/nspredef.c b/drivers/acpi/acpica/nspredef.c
index e3f08dcb5275..0091504df074 100644
--- a/drivers/acpi/acpica/nspredef.c
+++ b/drivers/acpi/acpica/nspredef.c
@@ -566,9 +566,35 @@ acpi_ns_check_package(struct acpi_predefined_data *data,
         case ACPI_PTYPE2_COUNT:
 
                 /*
-                 * These types all return a single package that consists of a
-                 * variable number of sub-packages.
+                 * These types all return a single Package that consists of a
+                 * variable number of sub-Packages.
+                 *
+                 * First, ensure that the first element is a sub-Package. If not,
+                 * the BIOS may have incorrectly returned the object as a single
+                 * package instead of a Package of Packages (a common error if
+                 * there is only one entry). We may be able to repair this by
+                 * wrapping the returned Package with a new outer Package.
                  */
+                if ((*elements)->common.type != ACPI_TYPE_PACKAGE) {
+
+                        /* Create the new outer package and populate it */
+
+                        status =
+                            acpi_ns_repair_package_list(data,
+                                                        return_object_ptr);
+                        if (ACPI_FAILURE(status)) {
+                                return (status);
+                        }
+
+                        /* Update locals to point to the new package (of 1 element) */
+
+                        return_object = *return_object_ptr;
+                        elements = return_object->package.elements;
+                        count = 1;
+                }
+
+                /* Validate each sub-Package in the parent Package */
+
                 for (i = 0; i < count; i++) {
                         sub_package = *elements;
                         sub_elements = sub_package->package.elements;
diff --git a/drivers/acpi/acpica/nsrepair.c b/drivers/acpi/acpica/nsrepair.c
index b64751eacc53..db2b2a99c3a8 100644
--- a/drivers/acpi/acpica/nsrepair.c
+++ b/drivers/acpi/acpica/nsrepair.c
@@ -149,3 +149,55 @@ acpi_ns_repair_object(struct acpi_predefined_data *data,
 
         return (AE_AML_OPERAND_TYPE);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_repair_package_list
+ *
+ * PARAMETERS:  Data                - Pointer to validation data structure
+ *              obj_desc_ptr        - Pointer to the object to repair. The new
+ *                                    package object is returned here,
+ *                                    overwriting the old object.
+ *
+ * RETURN:      Status, new object in *obj_desc_ptr
+ *
+ * DESCRIPTION: Repair a common problem with objects that are defined to return
+ *              a variable-length Package of Packages. If the variable-length
+ *              is one, some BIOS code mistakenly simply declares a single
+ *              Package instead of a Package with one sub-Package. This
+ *              function attempts to repair this error by wrapping a Package
+ *              object around the original Package, creating the correct
+ *              Package with one sub-Package.
+ *
+ *              Names that can be repaired in this manner include:
+ *              _ALR, _CSD, _HPX, _MLS, _PRT, _PSS, _TRT, TSS
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ns_repair_package_list(struct acpi_predefined_data *data,
+                            union acpi_operand_object **obj_desc_ptr)
+{
+        union acpi_operand_object *pkg_obj_desc;
+
+        /*
+         * Create the new outer package and populate it. The new package will
+         * have a single element, the lone subpackage.
+         */
+        pkg_obj_desc = acpi_ut_create_package_object(1);
+        if (!pkg_obj_desc) {
+                return (AE_NO_MEMORY);
+        }
+
+        pkg_obj_desc->package.elements[0] = *obj_desc_ptr;
+
+        /* Return the new object in the object pointer */
+
+        *obj_desc_ptr = pkg_obj_desc;
+        data->flags |= ACPI_OBJECT_REPAIRED;
+
+        ACPI_WARN_PREDEFINED((AE_INFO, data->pathname, data->node_flags,
+                              "Incorrectly formed Package, attempting repair"));
+
+        return (AE_OK);
+}