Device Root ACPI Root ¹PCI Host Controller Generic Random ISA PCI Bus ²PCI device 1 PCI device 2 PCI device 3 ³Driver child node UHCI-PCI Bridge UHCI Controller UHCI device 1 UHCI device 2 ¹PCI Host controller may be a child of ACPI root if the detection mechanism is ACPI instead of Legacy BIOS. Take a look at "busses/pci" for more details. B_DEVICE_FIXED_CHILD ²This device is exposed by the PCI bus. ³Your driver registers this node.