ACPI: document method tracing hooks

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/acpi/method-tracing.txt b/Documentation/acpi/method-tracing.txt
new file mode 100644
index 000000000000..f6efb1ea559a
--- /dev/null
+++ b/Documentation/acpi/method-tracing.txt
@@ -0,0 +1,26 @@
+/sys/module/acpi/parameters/:
+
+trace_method_name
+        The AML method name that the user wants to trace
+
+trace_debug_layer
+        The temporary debug_layer used when tracing the method.
+        Using 0xffffffff by default if it is 0.
+
+trace_debug_level
+        The temporary debug_level used when tracing the method.
+        Using 0x00ffffff by default if it is 0.
+
+trace_state
+        The status of the tracing feature.
+
+        "enabled" means this feature is enabled
+        and the AML method is traced every time it's executed.
+
+        "1" means this feature is enabled and the AML method
+        will only be traced during the next execution.
+
+        "disabled" means this feature is disabled.
+        Users can enable/disable this debug tracing feature by
+        "echo string > /sys/module/acpi/parameters/trace_state".
+        "string" should be one of "enable", "disable" and "1".