ACPICA: Add option to disable loading of SSDTs from the RSDT/XSDT

Optionally do not load any SSDTs from the RSDT/XSDT during
initialization.  This can be useful for overriding SSDTs
using DSDT overriding, thus useful for debugging ACPI
problems on some machines.  Lv Zheng. ACPICA BZ 1005.

References: https://bugs.acpica.org/show_bug.cgi?id=1005
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/acglobal.h

@@ -132,6 +132,12 @@ u8 ACPI_INIT_GLOBAL(acpi_gbl_truncate_io_addresses, FALSE);
  */
 u8 ACPI_INIT_GLOBAL(acpi_gbl_disable_auto_repair, FALSE);
 
+/*
+ * Optionally do not load any SSDTs from the RSDT/XSDT during initialization.
+ * This can be useful for debugging ACPI problems on some machines.
+ */
+u8 ACPI_INIT_GLOBAL(acpi_gbl_disable_ssdt_table_load, FALSE);
+
 /* acpi_gbl_FADT is a local copy of the FADT, converted to a common format. */
 
 struct acpi_table_fadt acpi_gbl_FADT;

drivers/acpi/acpica/tbxfload.c

@@ -53,8 +53,6 @@ ACPI_MODULE_NAME("tbxfload")
 /* Local prototypes */
 static acpi_status acpi_tb_load_namespace(void);
 
-static int no_auto_ssdt;
-
 /*******************************************************************************
  *
  * FUNCTION:    acpi_load_tables
@@ -180,8 +178,16 @@ static acpi_status acpi_tb_load_namespace(void)
 			continue;
 		}
 
-		if (no_auto_ssdt) {
-			printk(KERN_WARNING "ACPI: SSDT ignored due to \"acpi_no_auto_ssdt\"\n");
+		/*
+		 * Optionally do not load any SSDTs from the RSDT/XSDT. This can
+		 * be useful for debugging ACPI problems on some machines.
+		 */
+		if (acpi_gbl_disable_ssdt_table_load) {
+			ACPI_INFO((AE_INFO, "Ignoring %4.4s at %p",
+				   acpi_gbl_root_table_list.tables[i].signature.
+				   ascii, ACPI_CAST_PTR(void,
+							acpi_gbl_root_table_list.
+							tables[i].address)));
 			continue;
 		}
 
@@ -376,14 +382,3 @@ acpi_status acpi_unload_parent_table(acpi_handle object)
 }
 
 ACPI_EXPORT_SYMBOL(acpi_unload_parent_table)
-
-static int __init acpi_no_auto_ssdt_setup(char *s) {
-
-        printk(KERN_NOTICE "ACPI: SSDT auto-load disabled\n");
-
-        no_auto_ssdt = 1;
-
-        return 1;
-}
-
-__setup("acpi_no_auto_ssdt", acpi_no_auto_ssdt_setup);

drivers/acpi/osl.c

@@ -1715,6 +1715,17 @@ acpi_status acpi_os_release_object(acpi_cache_t * cache, void *object)
 }
 #endif
 
+static int __init acpi_no_auto_ssdt_setup(char *s)
+{
+        printk(KERN_NOTICE PREFIX "SSDT auto-load disabled\n");
+
+        acpi_gbl_disable_ssdt_table_load = TRUE;
+
+        return 1;
+}
+
+__setup("acpi_no_auto_ssdt", acpi_no_auto_ssdt_setup);
+
 acpi_status __init acpi_os_initialize(void)
 {
 	acpi_os_map_generic_address(&acpi_gbl_FADT.xpm1a_event_block);

include/acpi/acpixf.h

@@ -80,6 +80,7 @@ extern bool acpi_gbl_enable_aml_debug_object;
 extern u8 acpi_gbl_copy_dsdt_locally;
 extern u8 acpi_gbl_truncate_io_addresses;
 extern u8 acpi_gbl_disable_auto_repair;
+extern u8 acpi_gbl_disable_ssdt_table_load;
 
 /*
  * Hardware-reduced prototypes. All interfaces that use these macros will