- Simplify the amount of work that has be done for each architecture by pushing more of the truly MI code down into the PCI bus driver. - Don't bind MSI-X indicies to IRQs so that we can allow a driver to map multiple MSI-X messages into a single IRQ when handling a message shortage. Note that as with the previous MSI MFC, this does not yet include the 'pci_remap_msix()' function.