Sending audio data to a user mode application from Virtual Audio Driver

Question

I have my current task to send audio data from virtual audio driver to user mode application.

First I need to create an instance of that virtual audio driver from an user mode application ...

Please see the code snippet below

//Generating the device info
//That works
SetupDiGetClassDevs( &KSCATEGORY_AUDIO, NULL, NULL,  DIGCF_PRESENT|DIGCF_DEVICEINTERFACE );

//Enumerating device interface
//That works
SetupDiEnumDeviceInterfaces(dev_info, &DeviceInfoData, &KSCATEGORY_AUDIO, i, &did);

//Getting the path to device (pdd)
//That works
bRes = SetupDiGetDeviceInterfaceDetail(dev_info, &did, pdd, required_size, NULL, NULL);

//Handle to the device
//That works
HANDLE hHandle = CreateFile( pdd->DevicePath, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING,
            FILE_ATTRIBUTE_NORMAL, NULL);

//Passing the Handle
//That fails
//PData is the Out buffer where we get the driver sending value
bool bRc = DeviceIoControl ( hHandle,
                         (DWORD)IOCTL_SIOCTL_METHOD_OUT_DIRECT,  NULL, 0, &PData,
               sizeof( PData), &bytesReturned, NULL );

Could you please point out the reason?

For that above user mode application I used to write a piece of IOCTL code as follows...

NTSTATUS IoCtlHandler(PDEVICE_OBJECT pDeviceObject, PIRP Irp)
{
    PAGED_CODE();
    UINT dwDataSize = 0;
    PBYTE pReturnData ;

       pReturnData = (PBYTE)"IOCTL - Direct In I/O From Kernel Welcome to the world of   Portcl";
    dwDataSize = sizeof("IOCTL - Direct In I/O From Kernel! Welcome to the world of Portcl");

    //Point to a certain IRP location
     pIoStackIrp = IoGetCurrentIrpStackLocation(Irp);

     if(pIoStackIrp) 
     {

         switch(pIoStackIrp->Parameters.DeviceIoControl.IoControlCode)
         {
        //that ioctl  i pass inside the DeviceIoControl function
               case IOCTL_SIOCTL_METHOD_OUT_DIRECT:
             {
                 pOutputBuffer = NULL;
                 NtStatus = STATUS_UNSUCCESSFUL;

                 if(Irp->MdlAddress)
                 {
                                   pOutputBuffer = MmGetSystemAddressForMdlSafe(Irp-    >MdlAddress, NormalPagePriority);
                 }
                                                                                                          RtlCopyBytes(pOutputBuffer, pReturnData, dwDataSize);

                 break;
             }
         }
     }

     Irp->IoStatus.Information = dwDataSize;
     Irp->IoStatus.Status = NtStatus;

    //After all complete the IRP structure  
        //As it is a adapter driver we pass this information to handle by adapter itself
    NtStatus = PcDispatchIrp(pDeviceObject, Irp);

    return NtStatus;
}

Could you please point out my mistake.For my testing purpose I am just passing a string (IOCTL - Direct In I/O From Kernel Welcome to the world of Portcl") to the output buffer later on I would replace it by audio data...Why deviceIoControl fails though I get the string whatever I passes in driver but the bytesReturn value always coming as a random value with bRes value always false...