POLLING_INTERVAL
!IS_SUPPORTED_ATTR(df->governor->attrs, POLLING_INTERVAL))
!IS_SUPPORTED_ATTR(df->governor->attrs, POLLING_INTERVAL))
IS_SUPPORTED_ATTR(df->governor->attrs, POLLING_INTERVAL))
if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
timeout = (timeout + POLLING_INTERVAL - 1) / POLLING_INTERVAL;
msleep(POLLING_INTERVAL);