1. A context switching method for a processing pipeline, comprising the steps of: issuing a request-to-halt signal to a plurality of pipeline processing units in the processing pipeline, wherein each of the pipeline processing units is serially connected to another pipeline processing unit or to a frame buffer and is configured to process graphics data; receiving a plurality of status signals from the pipeline processing units in response to the request-to-halt signal, wherein a first status signal includes a not-idle signal indicating that a first pipeline processing unit is currently executing instructions, a second status signal includes an idle signal indicating that a second pipeline processing unit has completed executing all current instructions, and a third status signal includes a halted signal indicating that a third pipeline processing unit has not completed executing all instructions currently being executed by the third pipeline processing unit and has halted execution of the instructions currently being executed; once the first pipeline processing unit is also either idle or halted, issuing a stay-halted signal to the first, second, and third pipeline processing units to stay idle or halted based on the plurality of status signals; storing states of the pipeline processing units; and restoring previously stored states of the pipeline processing units.