Memory controller hub interface

A computer system comprising:

• a CPU;
• a display device;
• a system memory, the system memory adapted to store video data and non-video data;
• and
• a memory controller hub coupled to the CPU and coupled to the system memory, the memory controller hub comprising:
• an internal graphics subsystem adapted to perform graphics operations on graphics data;
• and
• interface circuitry adapted selectively to couple the internal graphics subsystem to a local memory through electrical connectors and to couple the memory controller hub to an external graphics controller through the same electrical connectors.

A computer system comprising:

• a CPU;
• a display device;
• a system memory, the system memory being adapted to store video data and non-video data;
• and
• a memory controller hub coupled to the CPU and coupled to the system memory, the memory controller hub comprising:
• an internal graphics subsystem adapted to perform graphics operations on graphics data;
• and
• interface circuitry adapted selectively to couple the internal graphics subsystem to a local memory through an accelerated graphics port and to couple the memory controller hub to an external graphics controller through the accelerated graphics port.

A method of initializing a memory controller hub of a computer system, the method comprising:

• sending an outgoing signal within the computer system to inquire if an external graphics controller is coupled to the memory controller hub;
• receiving an incoming signal within the computer system in response to the outgoing signal, the incoming signal indicating whether an external graphics controller is coupled to the memory controller hub;
• activating interface circuitry of the memory controller hub for transferring signals between the memory controller hub and the external graphics controller through electrical connectors if the incoming signal indicates that an external graphics controller is coupled to the memory controller hub;
• and activating the interface circuitry for transferring signals between an internal graphics subsystem of the memory controller hub and a local memory through the same electrical connectors if the incoming signal indicates that an external graphics controller is not coupled to the memory controller hub.

Instructions embodied in a machine-readable medium, the instructions being capable of causing an electronic device to:

• send an outgoing signal within a computer system to inquire if an external graphics controller is coupled to a memory controller hub of the computer system;
• receive an incoming signal within the computer system in response to the outgoing signal, the incoming signal indicating whether an external graphics controller is coupled to the memory controller hub;
• activate interface circuitry of the memory controller hub for transferring signals between the memory controller hub and the external graphics controller through electrical connectors if the incoming signal indicates that an external graphics controller is coupled to the memory controller hub;
• and activate the interface circuitry for transferring signals between an internal graphics subsystem of the memory controller hub and a local memory through the same electrical connectors if the incoming signal indicates that an external graphics controller is not coupled to the memory controller hub.