Fail AcpiEnable if ACPI tables not loaded.

AcpiEnable will now fail if all of the required ACPI tables are not loaded (FADT, FACS, DSDT). BZ 477

source/components/events/evxfevnt.c

@@ -1,7 +1,7 @@
 /******************************************************************************
  *
  * Module Name: evxfevnt - External Interfaces, ACPI event disable/enable
- *              $Revision: 1.90 $
+ *              $Revision: 1.91 $
  *
  *****************************************************************************/
 
@@ -147,6 +147,15 @@ AcpiEnable (
     ACPI_FUNCTION_TRACE (AcpiEnable);
 
 
+    /* ACPI tables must be present */
+
+    if (!AcpiTbTablesLoaded ())
+    {
+        return_ACPI_STATUS (AE_NO_ACPI_TABLES);
+    }
+
+    /* Check current mode */
+
     if (AcpiHwGetMode() == ACPI_SYS_MODE_ACPI)
     {
         ACPI_DEBUG_PRINT ((ACPI_DB_INIT, "System is already in ACPI mode\n"));

source/components/tables/tbutils.c

@@ -1,7 +1,7 @@
 /******************************************************************************
  *
  * Module Name: tbutils   - table utilities
- *              $Revision: 1.86 $
+ *              $Revision: 1.87 $
  *
  *****************************************************************************/
 
@@ -130,6 +130,33 @@ AcpiTbGetRootTableEntry (
     ACPI_NATIVE_UINT        TableEntrySize);
 
 
+/*******************************************************************************
+ *
+ * FUNCTION:    AcpiTbTablesLoaded
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      TRUE if required ACPI tables are loaded
+ *
+ * DESCRIPTION: Determine if the minimum required ACPI tables are present
+ *              (FADT, FACS, DSDT)
+ *
+ ******************************************************************************/
+
+BOOLEAN
+AcpiTbTablesLoaded (
+    void)
+{
+
+    if (AcpiGbl_RootTableList.Count >= 3)
+    {
+        return (TRUE);
+    }
+
+    return (FALSE);
+}
+
+
 /*******************************************************************************
  *
  * FUNCTION:    AcpiTbPrintTableHeader

source/include/actables.h

@@ -1,7 +1,7 @@
 /******************************************************************************
  *
  * Name: actables.h - ACPI table management
- *       $Revision: 1.62 $
+ *       $Revision: 1.63 $
  *
  *****************************************************************************/
 
@@ -209,6 +209,10 @@ AcpiTbSetTableLoadedFlag (
 /*
  * tbutils - table manager utilities
  */
+BOOLEAN
+AcpiTbTablesLoaded (
+    void);
+
 void
 AcpiTbPrintTableHeader(
     ACPI_PHYSICAL_ADDRESS   Address,