typedef struct _PI_BUS_EXTENSION
{
     ULONG Flags;
     UCHAR NumberCSNs;
     UCHAR * ReadDataPort;
     UCHAR DataPortMapped;
     UCHAR * AddressPort;
     UCHAR AddrPortMapped;
     UCHAR * CommandPort;
     UCHAR CmdPortMapped;
     ULONG NextSlotNumber;
     SINGLE_LIST_ENTRY DeviceList;
     SINGLE_LIST_ENTRY CardList;
     PDEVICE_OBJECT PhysicalBusDevice;
     PDEVICE_OBJECT FunctionalBusDevice;
     PDEVICE_OBJECT AttachedDevice;
     ULONG BusNumber;
     SYSTEM_POWER_STATE SystemPowerState;
     DEVICE_POWER_STATE DevicePowerState;
} PI_BUS_EXTENSION, *PPI_BUS_EXTENSION;

Windows Vista Kernel Structures