Re: [libusb] Transfer timeout

[Tim R. <ti...@pr...>]

dus...@em... wrote:
>
> I don't monitor my device using Device Monitoring Studio when the 
> reading starts to timeout (I have only 10min free version).
>
Then you have chosen the wrong tool.  There are other free USB 
monitoring tools that do not have time limitations.  Since you're on 
Windows, you could actually use the Microsoft Message Analyzer to track 
the I/O traffic, but it tends to be extremely opaque.  If you're just 
doing USB 2.0, there are hardware USB bus analyzers today that are quite 
affordable.  They would show you bus problems.


> When libusb_interrupt_transfer for interrupt IN endpoint is called on 
> the host side I receive no USB interrupt on the device side (the 
> device is NXP Kinetis MCU with their USB stack v2.1). What can cause 
> libusb read to timeout without submitting any transfer on the USB bus 
> (because if there was any transfer I would see it on the device's side 
> - in USB interrupt routine)?
>
Nothing.  If there is no error condition, the host controller will 
continue to send an IN token every time your time slot comes up until 
you respond.


>
> This is debug log of libusb_bulk_transfer that timeouts without any 
> data even though USB device has some data available to be sent:
>
You need to show us the last successful transfer as well.  The key 
question is, what is different?

-- 
Tim Roberts, ti...@pr...
Providenza & Boekelheide, Inc.