ACPI: Disable _GTS and _BFS support by default
Executing BIOS code paths not exercised by Windows
tends to get Linux into trouble.
However, if a system does benefit from _GTS or _BFS,
acpi.gts=1 an acpi.bfs=1 are now available to enable them.
http://bugzilla.kernel.org/show_bug.cgi?id=13041
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/hwsleep.c b/drivers/acpi/acpica/hwsleep.c
index baa5fc0..db307a3 100644
--- a/drivers/acpi/acpica/hwsleep.c
+++ b/drivers/acpi/acpica/hwsleep.c
@@ -211,6 +211,12 @@
ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_prep)
+static unsigned int gts, bfs;
+module_param(gts, uint, 0644);
+module_param(bfs, uint, 0644);
+MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
+MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
+
/*******************************************************************************
*
* FUNCTION: acpi_enter_sleep_state
@@ -278,16 +284,18 @@
return_ACPI_STATUS(status);
}
- /* Execute the _GTS method */
+ if (gts) {
+ /* Execute the _GTS method */
- arg_list.count = 1;
- arg_list.pointer = &arg;
- arg.type = ACPI_TYPE_INTEGER;
- arg.integer.value = sleep_state;
+ arg_list.count = 1;
+ arg_list.pointer = &arg;
+ arg.type = ACPI_TYPE_INTEGER;
+ arg.integer.value = sleep_state;
- status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
- if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
- return_ACPI_STATUS(status);
+ status = acpi_evaluate_object(NULL, METHOD_NAME__GTS, &arg_list, NULL);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ return_ACPI_STATUS(status);
+ }
}
/* Get current value of PM1A control */
@@ -513,18 +521,19 @@
}
}
- /* Execute the _BFS method */
+ if (bfs) {
+ /* Execute the _BFS method */
- arg_list.count = 1;
- arg_list.pointer = &arg;
- arg.type = ACPI_TYPE_INTEGER;
- arg.integer.value = sleep_state;
+ arg_list.count = 1;
+ arg_list.pointer = &arg;
+ arg.type = ACPI_TYPE_INTEGER;
+ arg.integer.value = sleep_state;
- status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
- if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
- ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
+ status = acpi_evaluate_object(NULL, METHOD_NAME__BFS, &arg_list, NULL);
+ if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+ ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));
+ }
}
-
return_ACPI_STATUS(status);
}
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 779e4e5..9042875 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -713,6 +713,32 @@
acpi_enter_sleep_state(ACPI_STATE_S5);
}
+/*
+ * ACPI 2.0 created the optional _GTS and _BFS,
+ * but industry adoption has been neither rapid nor broad.
+ *
+ * Linux gets into trouble when it executes poorly validated
+ * paths through the BIOS, so disable _GTS and _BFS by default,
+ * but do speak up and offer the option to enable them.
+ */
+void __init acpi_gts_bfs_check(void)
+{
+ acpi_handle dummy;
+
+ if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__GTS, &dummy)))
+ {
+ printk(KERN_NOTICE PREFIX "BIOS offers _GTS\n");
+ printk(KERN_NOTICE PREFIX "If \"acpi.gts=1\" improves suspend, "
+ "please notify linux-acpi@vger.kernel.org\n");
+ }
+ if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__BFS, &dummy)))
+ {
+ printk(KERN_NOTICE PREFIX "BIOS offers _BFS\n");
+ printk(KERN_NOTICE PREFIX "If \"acpi.bfs=1\" improves resume, "
+ "please notify linux-acpi@vger.kernel.org\n");
+ }
+}
+
int __init acpi_sleep_init(void)
{
acpi_status status;
@@ -771,5 +797,6 @@
* object can also be evaluated when the system enters S5.
*/
register_reboot_notifier(&tts_notifier);
+ acpi_gts_bfs_check();
return 0;
}