A system and method for power management by providing advance notice of events. The method includes snooping a register of an operating system timer to determine a timer period associated with a scheduled event. A unit of a computer system is identified that is in a low power state. A wake up latency of the unit is determined that is based on the low power state. An advance period is determined based on the wake up latency. An advance notice of the operating system timer is triggered based on the timer period and the advance period to wake up the unit.