Stefan Reinauer stepan@coresystems.de writes:
Segher Boessenkool wrote:
In practice the subsystem vendor IDs are quite arbitrary and definitely not the same for all PCI devices per mainboard
They aren't even allowed to be the same for all devices on a mainboard: the subsystem IDs should uniquely identify the device, without having to look at the "regular" IDs as well.
Again, mind me asking. Where did you find this definition?
Section 6.2.4 of the PCI specification states:
These registers are used to uniquely identify the add-in card or subsystem where the PCI device resides. The provide a mechanism for add-in card vendors to distinguish their add-in cards from one another even though the add-in cards may have the same PCI controller on them (and therefore the same Vendor ID and Device ID).
Or in paraphrase they identify the PCB the IC sits on.
Eric