Patent ID: 8650349

Claim:
A method comprising: receiving, at a first virtual bridge in a south chip, a first secondary bus identifier that identifies a bus that is immediately downstream from the first virtual bridge, a first subordinate bus identifier that identifies a highest bus identifier of all of buses reachable downstream from the first virtual bridge, and a first MMIO bus address range from a first north chip, wherein the first north chip is connected to the south chip via a first point-to-point connection; storing, at the first virtual bridge, the first secondary bus identifier, the first subordinate bus identifier, and the first MMIO bus address range; receiving, at a second virtual bridge in the south chip, a second secondary bus identifier that identifies a bus that is immediately downstream from the second virtual bridge, a second subordinate bus identifier that identifies a highest bus identifier of all of the buses reachable downstream from the second virtual bridge, and a second MMIO bus address range from a second north chip, wherein the second north chip is connected to the south chip via a second point-to-point connection; storing, at the second virtual bridge, the second secondary bus identifier, the second subordinate bus identifier, and the second MMIO bus address range, wherein the first virtual bridge and the second virtual bridge are connected to a shared egress port; receiving, at the first virtual bridge via a shared ingress port, a first configuration write command that comprises a first command bus identifier, a first virtual bridge identifier that identifies the first virtual bridge, and a first device MMIO address range; comparing, at the first virtual bridge, the first command bus identifier to the first secondary bus identifier and the first subordinate bus identifier; and if the first secondary bus identifier and the first subordinate bus identifier encompass the first command bus identifier, sending the first configuration write command from the first virtual bridge to a device connected to the shared egress port.