National Instruments Corporation

Robert D Ross

Craig S Jones

Jonathan W Hearn

Eric R Gardiner

Mark R Wetzel

Richard C Thrapp

A selectively transparent bridge facilitates a PCI device presenting itself to the host as a PCI-to-PCI bridge but selectively hiding and isolating hardware from the host bus. PCI configuration may be achieved through the standard PCI Express configuration mechanisms, but instead of configuring devices directly, a configuration processor in the selectively transparent bridge may intercept the configuration packets from the host, and create a virtual configuration to alter how the bus topology appears to the host. Devices are selectively hidden and managed by the configuration processor, resulting in simplified complexity and bus depth. Since the selectively transparent bridge appears to the host as a transparent bridge, no special drivers or resource preallocations are required, although the selectively transparent bridge fully supports special drivers and/or resource preallocations. Devices located/connected downstream of the bridge may therefore function with unmodified drivers.

Selectively transparent bridge for peripheral component interconnect express bus system

Selectively transparent bridge for peripheral component interconnect express bus systems

Enumerating an expanded bus system in a system. The expanded bus system may include a first bus, a bridge coupled to the first bus, and a second bus coupled to the bridge, where the second bus includes one or more downstream bus ports. One or more of the downstream bus ports may initially be masked. An initial bus enumeration may be performed during system boot, which may not include enumerating the masked bus ports. After the initial bus enumeration, the masked bus ports may be unmasked. An operating system may re-enumerate the bus system, which may include enumerating the no-longer-masked bus ports.

Bus enumeration in a system with multiple buses

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Pflugerville, TX, United States of America

Robert D Ross