[ACPI] fix 2.6.13 boot hang regression on HT box w/ broken BIOS

[linux-2.6-omap-h63xx.git] / drivers / acpi / tables / tbutils.c

diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index 5bcafebb9ddfe64314e7259b3a94e049b1b4ffe4..4b2fbb592f4933cf8b8138efe64f558c194a96fe 100644 (file)
--- 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",