10.6.6 S.M.A.R.T. operation with power management modes
It is recommended that, when a host system utilizes both the power management and S.M.A.R.T. features,
the system enable the device's attribute autosave feature to allow the device's automatic attribute saving
upon receipt of STANDBY IMMEDIATE or SLEEP commands. If the device has been set to utilize the
standby timer, the devce also saves attributes values prior to going from an Idle state to Standby state.
77
General Operation Descriptions