Communication to Cypress USB Driver is interrupted when user remove athumbdrive in Windows 7

Hi,

Is anybody else experiencing this problem? It only happens in Windows
7. I tried it in Windows XP and could not reproduce there. Basically
I have a C++ app that recieves streaming data from our firmware. In a
separate thread I have a loop that calls BeginDataXfer() (Cypress USB
API Call) and when the event is signaled it calls FinishDataXfer()
(Cypress USB API Call). Everything is working fine until a user
inserts a thumbdrive to do other stuff and when he pulled it out I get
this error from FinishDataXfer(). This happens 50% of the time, so I
think it's a timing issue but I don't know how to work around it.

Here's my environment:

MS Visual Studio 2010

32-bit Windows 7 Professional,

Cypress driver 3.4.2.0,

The chip we are using is the Cypress Chip CY7C68001-56PVC.

The application is as a high speed USB interface to the DSP processor.

Here's a code snippet within the thread:

case WAIT_OBJECT_0+2: //overlapped read operation done

{
if(pInContext!=NULL && BulkInEpt!=NULL)
{
nLength=nBufferSize;

::ResetEvent(t_osRead.hEvent);
if(BulkInEpt->FinishDataXfer(szReceiveBuffer, nLength,
&t_osRead,pInContext))
{
szReceiveBuffer[nLength]=0;
pThis->UpdateTotalXFerBytes(nLength);
pThis->ApppendToReplyProcessQueue(szReceiveBuffer,
nLength);

//Start an async. read again
nLength=nBufferSize;

pInContext=BulkInEpt-
>BeginDataXfer(szReceiveBuffer,nLength,&t_osRead );

// be nice and make sure giving time to
ReplyProcessThread

Sleep(0);
}
else
{
DWORD dwLastError=::GetLastError();
MessageBox.Show( "Reply-receive failed,
reconnecting...error code"+dwLastError);

}
}
}

break;
BTW, the GetLastError() always returns ERROR_IO_PENDING even before
the user removes a thumbdrive which another interesting phenomena.
Any insight would be appreciated.

Thank you.

On Feb 22, 7:22*pm, Marlon <mbaldov...@gmail.com> wrote:
> Hi,
>
> Is anybody else experiencing this problem? *It only happens in Windows
> 7. *I tried it in Windows XP and could not reproduce there. *Basically
> I have a C++ app that recieves streaming data from our firmware. *In a
> separate thread I have a loop that calls BeginDataXfer() (Cypress USB
> API Call) and when the event is signaled it calls FinishDataXfer()
> (Cypress USB API Call). *Everything is working fine until a user
> inserts a thumbdrive to do other stuff and when he pulled it out I get
> this error from FinishDataXfer(). *This happens 50% of the time, so I
> think it's a timing issue but I don't know how to work around it.
>
> Here's my environment:
>
> MS Visual Studio 2010
>
> 32-bit Windows 7 Professional,
>
> Cypress driver 3.4.2.0,
>
> The chip we are using is the Cypress Chip CY7C68001-56PVC.
>
> The application is as a high speed USB interface to the DSP processor.
>
> Here's a code snippet within the thread:
>
> case WAIT_OBJECT_0+2: //overlapped read operation done
>
> {
> * *if(pInContext!=NULL && BulkInEpt!=NULL)
> * *{
> * * * *nLength=nBufferSize;
>
> * * * * ::ResetEvent(t_osRead.hEvent);
> * * * * if(BulkInEpt->FinishDataXfer(szReceiveBuffer, nLength,
> &t_osRead,pInContext))
> * * * * *{
> * * * * * * * * szReceiveBuffer[nLength]=0;
> * * * * * * * * pThis->UpdateTotalXFerBytes(nLength);
> * * * * * * * * pThis->ApppendToReplyProcessQueue(szReceiveBuffer,
> nLength);
>
> * * * * * * * *//Start an async. read again
> * * * * * * * * *nLength=nBufferSize;
>
> * * * * * * * * *pInContext=BulkInEpt-
>
> >BeginDataXfer(szReceiveBuffer,nLength,&t_osRead );
>
> * * * * * * * * *// be nice and make sure giving time to
> ReplyProcessThread
>
> Sleep(0);
> * * * * * }
> * * * * *else
> * * * * * {
> * * * * * * * * * DWORD dwLastError=::GetLastError();
> * * * * * * * * * MessageBox.Show( "Reply-receive failed,
> reconnecting...error code"+dwLastError);
>
> * * * * * *}
> * * * *}
> *}
>
> break;
> BTW, the GetLastError() always returns *ERROR_IO_PENDING even before
> the user removes a thumbdrive which another interesting phenomena.
> Any insight would be appreciated.
>
> Thank you.

The workaround in this Knowledge Base article worked after rebooting
the pc. But I have to use the "Safely Remove Hardware and Media" from
the system tray for it to work properly. If I just remove the USB
thumbdrive I still get the disconnection error.

http://support.microsoft.com/kb/2401954