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Last Post 03 Aug 2011 05:28 AM by  ckw089
USB Failed GetDescriptor(iProduct & iSerialNumber)
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03 Aug 2011 05:28 AM

    I am using Zoom OMAP L138 eXperimenter Kit (SDK-XOMAPL138-10-6408R-B) and DaVinci-PSP-SDK-

    I have configured the Linux kernel as USB device (gadget). I have tried USB Ethernet/RNDIS Gadget (g_ether.ko), USB Serial Gadget (g_serial.ko), and File Storage Gadget (g_file_storage.ko).

    I have captured the USB bus traffic during enuemeration for these gadgets. All of them failed GetDescriptor(String iProduct) and GetDescriptor(String iSerialNumber) request.

    Investigation show that the USB Controller does not send ACK packet for these requests, and no interrupt is generated to firmware. These requests are ignored by the HW.

    As I experimented further with different wLength for these requests, I will get different result. For example, if wLength =256, I have better chances to have the request successful.

    Setup packet with wLength = 255, always failed the request.
    80 06 03 03 09 04 FF 00

    Setup packet with wLength = 256, always successful with the request.
    80 06 03 03 09 04 00 01

    Not sure LogicPD aware of this issue. Hopefully LogicPD can provide some advice or suggestion.

    I have better descriptor of this issue in TI E2E Community forum.

    L138: USB Failed GetDescriptor(iProduct) and GetDescriptor(iSerialNumber) request

    OMAPL138: missing standard request during USB 2.0 enumeration

    kc Wong
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