US Patent 7629978 Multichip rendering with state control

Circuits, methods, and apparatus that provide multiple graphics processor systems where specific graphics processors can be instructed to not perform certain rendering operations while continuing to receive state updates, where the state updates are included in the rendering commands for these rendering operations. One embodiment provides commands instructing a graphics processor to start or stop rendering geometries. These commands can be directed to one or more specific processors by use of a set-subsystem device mask.