Re: libusb_interrupt_transfer( devh, 0x81, buf, sizeof( buf ), &transfered, SL_TRANSFER_TIMEOUT_50MS ) skips dumping data into buf at even iteration in OpenBSD.

[Xiaofan C. <xia...@gm...>]

On Wed, Oct 24, 2012 at 5:54 AM, Liu Wang <li...@su...> wrote:
> Looks only at odd iteration of launching "./test getkey" does r =
> libusb_interrupt_transfer( devh, 0x81, buf, sizeof( buf ), &transfered,
> SL_TRANSFER_TIMEOUT_50MS ) dump correct data into buf.

> But from ellisys USB Explorer it could be seen in every
> iteration of launching "./test getkey" the get key request has been
> successfully send to our LCD front panel device and the device has
> sent back the correct key code corresponding to key pressing operation.

Just a guess here, this kind of problem sometimes comes from the
wrong data toggle (buggy firmware). The OpenBSD backend and/or the
OpenBSD USB stack may not be as robust as Linux in terms of dealing
with such problems and may reject the data. Common problems with
the firmware are bugs with regard to set interface command.

Since you have a Hardware USB Analyzer, you can check whether it
is indeed a data toggle issue or not.


-- 
Xiaofan