On Mon, Mar 24, 2003 at 11:51:50AM -0800, Kallol Biswas wrote:
> Hi,
> I am new to USB world and looking for clarification on usb
> printer's
> behavior when transferring data with size multiple of wMaxPacketSize.
>
> I have been running redhat 7.1 (linux kernel 2.4.2-2) on x86 PC with a
> USB 1.1 controller. There is a target mode printer driver running on the
>
> other side.
>
> On the host the device file is /dev/usb/lp0.
> If a data packet of 64 bytes is sent with
>
> "cat data8 > /dev/usb/lp0" , the size of data8 is 64, a zero length
> packet
> at the end of the transfer is not sent.
>
> Is this a correct behavior? How do we force the printer driver send
> a zero length packet at the end of a transfer if the packet size is
> a multiple of wMAxPacketSize?
If your device requires that a zero length packet be send for this
situation, then modify the transfer flags of the urb with
URB_ZERO_PACKET to cause this to happen.
Hope this helps,
greg k-h
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This archive was generated by hypermail 2b29 : Mon Mar 31 2003 - 22:00:18 EST