Abstract: An apparatus and method for efficiently performing power management for multiple clients of a semiconductor chip that supports remote manageability. In various implementations, a network interface receives a packet, and sends at least an indication of the packet to a manageability processing circuitry (MPC) of a processing node with multiple clients for processing tasks. The MPC determines whether a client or itself is a destination needed to process the packet. If the destination is the MPC, then packet processing is done by the MPC without involvement from the clients, which can be in an idle state. For example, the MPC can process a remote manageability packet requesting diagnostic information from one or more clients of the processing node. The network interface and the MPC use a sideband communication channel for data transmission, which foregoes lane training for further reduction in latency and power consumption.

Abstract: Systems, apparatuses, and methods for a host controller inferring idleness based on activity generated by a bus-attached peripheral device are disclosed. A host controller detects activity by a first device attached to the host controller via a first bus. The host controller generates an activity vector based on the detected activity, and the host controller determines whether the activity vector indicates that the first device is only engaging in handshaking or control activity rather than data transfer. If the first device is merely communicating status information, then the host controller infers idleness and conveys an idleness indicator to a power manager. The power manager turns off power to system memory and/or other components based on the idleness indicator, but keeps enough power on to allow the host controller to communicate with the first device for handshaking or status purposes.