Patent ID: 8826047

Claim:
A system comprising: a first power management module configured to manage power states of a first device communicating with a system bus; and a second power management module including control registers configured to store statuses of the power states and one or more clocks of the first device, the second power management module configured to manage power consumption of the first device, independently of managing power consumption of a second device communicating with the system bus, by selectively supplying a power supply and one or more clock signals to the first device based on the statuses by writing to the control registers via a register bus, wherein the register bus is different than the system bus, and manage the power consumption of the first device by supplying the power supply and the one or more of the clock signals to the first device using one or more of (i) a first control signal used to transition the first device from a first power state to a second power state, (ii) a second control signal used to turn on or off the power supply to the first device, and (iii) a third control signal used to turn on or off one or more of the clocks of the first device, wherein in response to the second power management module writing to or reading from the control registers, a plurality of devices in a path from the second power management module to the first power management module are turned on.