Re: [Libusbx-devel] Getting "unsupported API call for 'open'" on Windows 8.1 libusb

[Bob T. <to...@se...>]

Hi, it checks the VID and PID

int is_correctdev( libusb_device *dev )
{
struct libusb_device_descriptor desc;
int r = libusb_get_device_descriptor( dev, &desc );

    //printf("Checking VID=0x%04x, PID=0x%04x\n", desc.idVendor,
desc.idProduct);
if( desc.idVendor == VENDOR_ID &&
      (desc.idProduct  == PRODUCT_ID)
  {
        //printf("device found: class=0x%x\n", desc.bDeviceClass);

return 1;
}
return 0;
}



On Thu, Jul 31, 2014 at 3:42 AM, Matthias Bolte <
mat...@go...> wrote:

> 2014-07-29 23:28 GMT+02:00 Bob Tausworthe <to...@se...>:
> > Sorry to trouble you but I've exhausted other options. We are developing
> a
> > composite HID/debug interace device and are using libusb 1.0 under 32 bit
> > Cygwin to access the debug interface portion. Everything is working fine
> on
> > Windows 7 and Linux but when we try to run the application on Windows 8,
> it
> > fails with the error :
> >
> > libusb: debug [unsupported_open] unsupported API call for 'open'
> > (unrecognized device driver)
> > libusb: debug [libusb_open] open 2.16 returns -12
> > ERROR: Unable to open usb device
> >
> > After reading some posts of people with similar issues, I tried all of
> the
> > drivers Zadig supports but didn't see any difference in behavior. I have
> > tried building under Win7 and Win8 but the results are the same. I am
> using
> > version 1.0.18 of libusb. The trace below was taken with the WinUSB
> driver
> > version 6.1.7600.16385.
> >
> > Any help you can give me to point me in the right direction would be
> > welcome. Here is the code I'm using to open our device and the trace
> > listing.
> >
> > Thanks
> >
> > Bob Tausworthe
> > to...@se...
> > Sentons, inc.
> >
> > int
> >
> > InitUSB(void)
> >
> > {
> >
> >    // Change these as needed to match idVendor and idProduct in your
> > device's device descriptor.
> >
> >    int device_ready = 0;
> >
> >    int result;
> >
> >   libusb_device **list;
> >
> >   libusb_device *found = NULL;
> >
> >   libusb_context *ctx = NULL;
> >
> >   int attached = 0;
> >
> >   result = libusb_init(&ctx);
> >
> >   if (result == 0) {
> >
> >   if (usb_trace_enabled)
> >
> >   libusb_set_debug(ctx,255); // LIBUSB_LOG_LEVEL_DEBUG,
> > LIBUSB_LOG_LEVEL_WARNING
> >
> >   ssize_t i = 0;
> >
> >   int err = 0;
> >
> >   ssize_t cnt = libusb_get_device_list(ctx, &list);
> >
> >   if (cnt < 0){
> >
> >     fprintf(stderr, "ERROR: no usb devices found\n" );
> >
> >     error();
> >
> >   }
> >
> >   // find our device. Note we are using the brute force method rather
> >
> >   // than open_device_with_vid_pid() because we need the device pointer
> >
> >   // to look at the config descriptor.
> >
> >   for(i = 0; i < cnt; i++){
> >
> >     libusb_device *device = list[i];
> >
> >     if( is_correctdev(device) ){
>
> How does the is_correctdev() function decide which device to pick?
>
> --
> Matthias Bolte
> http://photron.blogspot.com
>
>
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