Re: [Libusbx-devel] libusb_control_transfer() stalls

[Markus <li...@ne...>]

On Wed, 13  13:24 , Pete Batard wrote:
> Well, all I can say is that we seem to be getting a stall report by 
> WinUSB indeed.
...
> If you see the expected >0x4000 wValue, and the rest of the request is 
> the same, then the problem is likely to be with the device rather than 
> libusbx or WinUSB. Maybe there's a special mode that needs to be enabled 
> on the device to r/w beyond wValue 0x4000?

I don't see any value >0x4000, it's already at 0x4000 that the
problem occurs. Nevertheless, when looking at the URBs, I don't
spot any difference except for the address. I should mention
that it returns pretty quick in comparison to the good transfers
(1.2 ms vs. 250 us).

After a quick test with libusbK only (i.e. libusbK.sys and API),
I'm getting increasingly convinced that it's a device issue. I
inserted the following code into the xfer-control.c example and
see the stall at 0x4000 as well, with GetLastError() returning
31:

  memset(fwBuffer, 0, sizeof(fwBuffer));
  memOffset = 0x3F80;

  /*
  Use a vendor control transfer to transmit firmware bytes. (HostToDevice)
  */
  for (i = 48; i < 52 ; i++) 
  {
    memset(fwBuffer, i, sizeof(fwBuffer));
    setupPacket.BmRequest.Dir = BMREQUEST_DIR_HOST_TO_DEVICE;
    setupPacket.BmRequest.Type = BMREQUEST_TYPE_VENDOR;
    setupPacket.BmRequest.Recipient = BMREQUEST_RECIPIENT_DEVICE;
    setupPacket.Request = 0xA0;  // Cypress
    setupPacket.Value = memOffset;
    setupPacket.Index = 0x0000;
    setupPacket.Length = sizeof(fwBuffer);
    success = Usb.ControlTransfer(usbHandle, *((WINUSB_SETUP_PACKET*)&setupPacket), fwBuffer, 
      sizeof(fwBuffer) - 1, &txBytes, NULL);
    if (!success)
    {
      errorCode = GetLastError();
      printf("Usb.ControlTransfer failed. Win32Error=%u(0x%08X)\n", errorCode, errorCode);
      goto Done;
    }
    memOffset += 0x40;
  }


Thanks in advance,
/Markus


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