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    SubjectRe: [Patch] Increase USBFS Bulk Transfer size
    On Sat, Oct 15, 2011 at 03:04:28PM -0400, Alan Stern wrote:
    > On Sat, 15 Oct 2011, Johannes Stezenbach wrote:
    > > It would make a difference if the
    > > device violated the spec and sent 188 byte packets. However, the
    > > spec says a short packet terminates the transfer. But I wonder
    > > if this is really the case?
    > The device does not send short packets. If it did, the 24064-byte
    > transfers would end early.

    Re-reading the USB-2.0 standard, a short packet which terminates
    the transfer is defined by packet_size < wMaxPacketSize,
    not by packet_size < 512.
    Thus wMaxPacketSize == 188 (or 2*188) might be possible.

    There is a comment in linux/drivers/usb/host/ehci-q.c:

    /* The USB spec says that high speed bulk endpoints
    * always use 512 byte maxpacket. But some device
    * vendors decided to ignore that, and MSFT is happy
    * to help them do so. So now people expect to use
    * such nonconformant devices with Linux too; sigh.

    Maybe we should look at the descriptors?


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