1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index 5bcafebb9ddf..4b2fbb592f49 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -80,14 +80,24 @@ acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
         /* Examine all installed tables of this type */
 
         while (table_desc) {
-                /* Compare Revision and oem_table_id */
-
+                /*
+                 * If the table lengths match, perform a full bytewise compare. This
+                 * means that we will allow tables with duplicate oem_table_id(s), as
+                 * long as the tables are different in some way.
+                 *
+                 * Checking if the table has been loaded into the namespace means that
+                 * we don't check for duplicate tables during the initial installation
+                 * of tables within the RSDT/XSDT.
+                 */
                 if ((table_desc->loaded_into_namespace) &&
-                    (table_desc->pointer->revision ==
-                     new_table_desc->pointer->revision) &&
-                    (!ACPI_MEMCMP(table_desc->pointer->oem_table_id,
-                                  new_table_desc->pointer->oem_table_id, 8))) {
-                        /* This table is already installed */
+                    (table_desc->pointer->length ==
+                     new_table_desc->pointer->length)
+                    &&
+                    (!ACPI_MEMCMP
+                     ((const char *)table_desc->pointer,
+                      (const char *)new_table_desc->pointer,
+                      (acpi_size) new_table_desc->pointer->length))) {
+                        /* Match: this table is already installed */
 
                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
                                           "Table [%4.4s] already installed: Rev %X oem_table_id [%8.8s]\n",