18.2.1 Hot-plug PCI buses

The PCI bus driver in the EDK II does not support hot-plug events in the pre-boot environment. The PCI bus driver functions correctly with hot-plug-capable hardware, but the hot-add, hot-remove, and hot-replace events are only supported while an OS that supports hot-plug events is executing. The PCI bus driver requires updates to support hot-plug events in the pre-boot environment.