The Interrupts modes in the following section applies to AXI Bridge for PCIe Gen3 only. For DMA/Bridge Subsystem for PCIe in Bridge Mode, go to the next section.
Multiple interrupt modes can be configured during IP configuration, however only
one interrupt mode is used at runtime. If multiple interrupt modes are enabled by the
host after PCI bus enumeration at runtime, the core uses the MSI interrupt over Legacy
interrupt. Both MSI and Legacy interrupt modes are sent using the same int_msi_* interface, and the core automatically picks the
best available interrupt mode at runtime. MSI-X is implemented externally to the core
and uses a separate cfg_interrupt_msix_* interface. The
core does not prevent the use of MSI-X at any time even when other interrupt modes are
enabled, however, AMD recommends the use of MSI-X interrupt solely if
enabled over other interrupt modes even if they are all enabled at runtime.