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PCI class codes

Q: I understand PCI class codes are important, but I do not know why. Can you shed some light on this?

A: They are required by the PCI Specification. Class-code is a required register in a device's Configuration Space. That is the space that Open Firmware interrogates while detecting devices and entering the device and its properties and methods (if there are methods) into the device tree. For details, see the PCI Local Bus Specification 2.1/2.2 Section 6.2.1 Device Identification.

[Sep 05 2000]

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