1 files changed, 18 insertions, 16 deletions

diff --git a/drivers/acpi/tables/tbrsdt.c b/drivers/acpi/tables/tbrsdt.c
index b7ffe39..13c6ddb 100644
--- a/drivers/acpi/tables/tbrsdt.c
+++ b/drivers/acpi/tables/tbrsdt.c
@@ -159,8 +159,8 @@ cleanup:
  *
  * RETURN:      None, Address
  *
- * DESCRIPTION: Extract the address of the RSDT or XSDT, depending on the
- *              version of the RSDP
+ * DESCRIPTION: Extract the address of either the RSDT or XSDT, depending on the
+ *              version of the RSDP and whether the XSDT pointer is valid
  *
  ******************************************************************************/
 
@@ -174,16 +174,19 @@ acpi_tb_get_rsdt_address (
 
 	out_address->pointer_type = acpi_gbl_table_flags | ACPI_LOGICAL_ADDRESSING;
 
-	/*
-	 * For RSDP revision 0 or 1, we use the RSDT.
-	 * For RSDP revision 2 (and above), we use the XSDT
-	 */
-	if (acpi_gbl_RSDP->revision < 2) {
-		out_address->pointer.value = acpi_gbl_RSDP->rsdt_physical_address;
-	}
-	else {
+	/* Use XSDT if it is present */
+
+	if ((acpi_gbl_RSDP->revision >= 2) &&
+		acpi_gbl_RSDP->xsdt_physical_address) {
 		out_address->pointer.value =
 			acpi_gbl_RSDP->xsdt_physical_address;
+		acpi_gbl_root_table_type = ACPI_TABLE_TYPE_XSDT;
+	}
+	else {
+		/* No XSDT, use the RSDT */
+
+		out_address->pointer.value = acpi_gbl_RSDP->rsdt_physical_address;
+		acpi_gbl_root_table_type = ACPI_TABLE_TYPE_RSDT;
 	}
 }
 
@@ -211,10 +214,9 @@ acpi_tb_validate_rsdt (
 
 
 	/*
-	 * For RSDP revision 0 or 1, we use the RSDT.
-	 * For RSDP revision 2 and above, we use the XSDT
+	 * Search for appropriate signature, RSDT or XSDT
 	 */
-	if (acpi_gbl_RSDP->revision < 2) {
+	if (acpi_gbl_root_table_type == ACPI_TABLE_TYPE_RSDT) {
 		no_match = ACPI_STRNCMP ((char *) table_ptr, RSDT_SIG,
 				  sizeof (RSDT_SIG) -1);
 	}
@@ -236,11 +238,11 @@ acpi_tb_validate_rsdt (
 			acpi_gbl_RSDP->rsdt_physical_address,
 			(void *) (acpi_native_uint) acpi_gbl_RSDP->rsdt_physical_address));
 
-		if (acpi_gbl_RSDP->revision < 2) {
-			ACPI_REPORT_ERROR (("Looking for RSDT (RSDP->Rev < 2)\n"))
+		if (acpi_gbl_root_table_type == ACPI_TABLE_TYPE_RSDT) {
+			ACPI_REPORT_ERROR (("Looking for RSDT\n"))
 		}
 		else {
-			ACPI_REPORT_ERROR (("Looking for XSDT (RSDP->Rev >= 2)\n"))
+			ACPI_REPORT_ERROR (("Looking for XSDT\n"))
 		}
 
 		ACPI_DUMP_BUFFER ((char *) table_ptr, 48);