1. 根目录:
2. Documentation
3. acpi
4. method-tracing.txt

/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".