Hello all!

I have written simple usb device driver.
But it works wrong. My device has 2 bulk full-speed USB2.0 endpoints(IN and OUT).
It uses standard write() call for writing(OUT urb) into device.
usb_submit_urb() returns 0, which means all OK. Callback return OK. But sometimes no usb transfer happens and my device doesn't receive anything. It is very strange behavior and my GUI application fails when this happens because data order is corrupted.
It is all OK with read() call(IN urbs).

Maybe there is some bug in usbcore?
Can anyone please help me or point a direction to which I should look?

If you need I can post parts of code. The same error occurs on mandrivalinux kernel 2.6.18 and VectorLinux gold 6.0 kernel 2.6.27

Thanks!

Is the callback's error code zero in this case, too?
Does usbmon indicate that the data was sent?

Unlikely.

You should look at your driver's source code.

That would be helpful, since my crystal ball is under repair.

Thanks for answering me. I have found error in my driver.
I am developing real time application that's why it is hard to explain parts of code without knowing the whole project.

Sorry for wasting your time