METHOD FOR ADAPTIVE POWER MANAGEMENT OF A COMPUTER SYSTEM

A method and apparatus for improved computer system power management is described. A power management controller includes a plurality of device idle timers, each associated with a particular I/O device. Expiration of the device idle timers, and the placing of the associated I/O device into a powered-down state, is controlled by device idle time values programmed into timing registers. The device idle time values are regularly updated as a function of time of day, time of week, etc., to optimize power efficiency. The device idle time values are determined by monitoring and recording the history of I/O device use. Thus, an I/O device may be quickly powered-down during those time periods during which device activity is not expected, whereas the I/O device will be maintained in a powered-up state during those times when device activity is probable. Also included are device activation timers which activate a powered-down computer system or particular I/O device in anticipation of a subsequent system event.