Patent ID: 7216245

Claim:
A power management method applied to a computer system, which is going to enter a power-saving mode, the computer system comprising a CPU, a north bridge communicating with the CPU according to a hyper transport I/O link protocol, a south bridge, a power supply, and at least one peripheral electrically connected to the north bridge, the method comprising the steps of: enabling the CPU to output a power management signal to the south bridge via the north bridge; enabling the south bridge to respond with a stop clock cycle to the CPU according to the power management signal; enabling the CPU to respond with a stop grant message according to the stop clock signal; enabling the north bridge to receive the stop grant message and analyze a power supply mode in the stop grant message, and enabling the north bridge to output a state transition signal to the at least one peripheral if the power supply mode is to suspend a main power supplied from the power supply; enabling the at least one peripheral to respond with an acknowledge signal after the at least one peripheral finishes its state transition according to the state transition signal; enabling the north bridge to pass the stop grant message to the south bridge after the north bridge receives the acknowledge signal; enabling the south bridge to output a power control signal after the south bridge receives the stop grant message; and enabling the power supply to suspend a corresponding power after the power supply receives the power control signal; wherein the north bridge comprises a decoding unit for analyzing the power supply mode in the stop grant message; and the power supply mode is identified by analyzing, by the decoding unit, a system management action field (SMAF) in the stop grant message.