Method of performing bus arbitration between control chips in a chipset with preemptive capability

Abstract

A method is proposed for the purpose of performing bus arbitration between two control chips in a chipset with preemptive capability. The two control chips can be, for example, a North Bridge chip and a South Bridge chip, of which one is set as bus owner while the other is set as bus receiver at initializtion. During operation, in the event that the current bus receiver intends to carry out a high-priority transaction, it can issue a preemptive request to ask the bus owner to relinquish the control of the bus. In response to this preemptive request, the current bus owner will start a latency timer; and by the time the latency timer reaches its preset time, the current bus owner will unconditionally hand the bus to the current bus receiver, allowing the current bus receiver to become the bus owner, thereby using the bus to carry out the intended high-priority transaction. This preemptive scheme can help enhance the overall system communication perfomance.