Windows XP : How to Get USB device location from the disk drive letter

Question

When we connect USB mass storage device, two entries are created in the Device Manager: one under Disk Drive and another under USB as USB Mass Storage.

 HDEVINFO hDevInfo = SetupDiGetClassDevs(
                (LPGUID) &GUID_DEVCLASS_DISKDRIVE,      // USB Device Class
                NULL,
                NULL, 
                DIGCF_PRESENT); 

This will list the entry under Disk Drive

 HDEVINFO hDevInfo = SetupDiGetClassDevs(
                (LPGUID) &GUID_DEVCLASS_USB,        // USB Device Class
                NULL,
                NULL,
                DIGCF_PRESENT);

This will list all the USB devices.

Is there any way to map the entries obtained from the above two calls. I checked for device instance id of all the devices using SetupDiEnumDeviceInfo, but ids did not match

The reason I need to map these two entries is because I have to get the USB device location (Hub and Port) number

Thanks Praveen

Answer 1

The drive letter is associated with a volume/partition on the drive. You'll see this when you use the "safe disconnect" option in Windows, where it will list all the entities that will be removed.

So, check the device parent.

Answer 2

You could enumerate physical disk devices using the GUID_DEVINTERFACE_DISK. Using:

SetupDiGetClassDevs
(
    &GUID_DEVINTERFACE_DISK,
    NULL,
    NULL,
    DIGCF_PRESENT | DIGCF_DEVICEINTERFACE
)

Then, query the storage adapter descriptor.

STORAGE_PROPERTY_QUERY storageProperty;
//...setup
PSTORAGE_ADAPTER_DESCRIPTOR pstorageAdapterDesc;
pstorageAdapterDesc = (PSTORAGE_ADAPTER_DESCRIPTOR)LocallAlloc( LPTR, storageDescHeader.Size );

DeviceIoControl
(
    handle,
    IOCTL_STORAGE_QUERY_PROPERTY,
    &storageProperty, 
    sizeof( STORAGE_PROPERTY_QUERY ),
    pstorageAdapterDesc,
    storageDescHeader.Size,
    bytesReturned,
    NULL
)

In the descriptor, you could use the "BusType" and check for USB.