Re: [Libusb-devel] Need non-caching version of usb_get_descriptor

[Alan S. <st...@ro...>]

On Sat, 27 Nov 2010, Peter Stuge wrote:

> Drissel, Mark wrote:
> > I am using libusb-win32 v1.2.2.0.
> 
> Ok. As you may have seen on http://libusb.org/ already, libusb-win32
> is it's own project, although the intent is very much to switch users
> over onto libusb-1.0 when it is good enough.
> 
> 
> > I was hoping the libusb library would make it easy to exercise the
> > device enumeration routines in the firmware of my device.
> > Occasionally, I'm seeing the 17th and 18th bytes of the device
> > descriptor response filled with garbage.
> 
> Thanks for the explanation! libusb is not well suited for device
> enumeration debugging. The focus of libusb is data transfer from user
> space programs, and device enumeration takes place in the kernel well
> before libusb becomes relevant.
> 
> Sorry, you'll have to dig into a kernel. I'd recommend Linux.

How about using the non-win32 version of libusb?  Does Windows still 
intercept the libusb_control_message() version of the program?

Under Linux you don't even have to write your own test program.  There 
is a general usbtest program available in the kernel source, together 
with a corresponding testusb driver.  The two of them can carry out 
lots of different tests, including fetching the device descriptor.

Alan Stern