Product specifications

performing the necessary configuration processing for each discovered
PCI card.
Unfortunately, not all console firmware is created equal. In order to
configure all of your PCI cards installed in the PCI expansion system,
your console firmware must be able to traverse multiple levels of
bridges. In point of fact, the 255 bus limit is a theoretical maximum with
the practical limit somewhat lower (yet should still be a large number,
like 100).
Most modern console firmware and BIOS code allows multiple bridges
(and thus PCI buses) to be correctly configured. Certain older firmware
implementations, however, place an arbitrary limit on the number of
bridge levels that can be traversed during power-on configuration. Your
firmware should be PCI Specification 2.1 compliant in order to
effectively use a MAGMA PCI Expansion System. For "fan-out" and
"daisy chained" system configurations where more than one PCI
expansion system is being used, you should count all of the bridge
levels to your most deeply nested PCI bus to determine the maximum
number of bridge levels that must be traversed.