/* Returns 0 (no ACPI _BCL or _BCL invalid), or size of brightness map  */
static int __init tpacpi_check_std_acpi_brightness_support(void)
/* Returns 0 (no ACPI _BCL or _BCL invalid), or size of brightness map  */
static int __init tpacpi_check_std_acpi_brightness_support(void)
{
	int status;
	int bcl_levels = 0;
	void *bcl_ptr = &bcl_levels;
	if (!vid_handle) {
		TPACPI_ACPIHANDLE_INIT(vid);
	}
	if (!vid_handle)
		return 0;
	status = acpi_walk_namespace(ACPI_TYPE_METHOD, vid_handle, 3,
				     tpacpi_acpi_walk_find_bcl, NULL, NULL,
				     &bcl_ptr);
	if (ACPI_SUCCESS(status) && bcl_levels > 2) {
		tp_features.bright_acpimode = 1;
		return (bcl_levels - 2);
	}
	return 0;
}