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BF526 and USB: Truncated  endpoint 0 data

Question asked by G40 on Jul 10, 2012
Latest reply on Jul 24, 2012 by G40

I'm testing out various performance options with the BF526 EZBRD and USB bulk driver.

 

Under certain circumstances I am seeing packets on a Windows host that are 17 bytes long instead of the 18 that are reported sent. This is using the stock driver with PIO enabled in TransmitEpZeroBuffer() in adi_usb_hdr.c. There are no obvious errors on the device (Blackfin) side - no stalls or error bits.

 

The trace below is taken using Windows ETW packet logging. The correct idVendor = 0xFACE and idProduct = 0xFEEE

 

    + Urb: success, Function = URB_FUNCTION_CONTROL_TRANSFER, Length = 17, Flags 0x3

    + SetupPacket: GET_DESCRIPTOR

      fid_URB_TransferDataLength: 17 (0x11)

    - DataPackets:

     - DeviceDescriptor:

        bLength: 18 (0x12)

        bDescriptorType: 1 (0x1)

        bcdUSB: 512 (0x200)

        bDeviceClass: 0 (0x0)

        bDeviceSubClass: 0 (0x0)

        bDeviceProtocol: 0 (0x0)

        bMaxPacketSize0: 64 (0x40)

        idVendor: 60878 (0xEDCE)

        idProduct: 256 (0x100)

        bcdDevice: 513 (0x201)

        iManufacturer: 0 (0x0)

        iProduct: 1 (0x1)

        iSerialNumber: 0 (0x0)

 

The raw data is

12 01 00 02 00 00 00 40 CE ED 00 01 01 02 00 01 00

.......@Îí.......

 

Any help greatly appreciated.

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