Patent ID: 7467313

Claim:
A method for transmitting a power-saving command between a computer system and first and second system chips thereof, where a second register is defined in an input/output (I/O) system of the computer system, and a state of the first register is obtained by the second register to establish and execute the power saving command, the method comprising: transmitting the power saving command to the first system chip from a central processing unit (CPU); setting a first register in the first system chip; executing the power saving command and causing one or more first peripherals coupled to the first system chip to enter a power saving mode; monitoring a state of the second register, the second register being set in response to the one or more first peripherals entering the power saving mode; transmitting the power saving command to the second system chip from the central processing unit in response to the second register being set to a defined state; and in response to the power saving command, switching attached second peripherals to power saving mode.