Re: [libusb] Composite WinUSB interface claim fails

[<sch...@tw...>]

Hello there again,

 

Long story short:

It worked when I adjusted the device GUID.

For debugging/developing I always incremented the PID(hardware won't leave
my Desk and I don't have to cope with cached driver installations.. I
thought)

But I did not change the WCID device GUID(found in FW USB Stack).

I'm not sure why it broke in the first place. It's not a GUID that's listed
in any of the System-defined Device setup Classes, but the default one I got
with the Modification of the TI USB Stack.

 

So. Maybe you could please help me and point me to something where I find
out about these GUIDs. Or tell me if they are:

-device-unique?

-class-unique?

-just arbitrary random numbers I can make of?

 

Why did it break when I recycled the GUID on multiple different VID:PID
combinations?

 

On 

https://github.com/libusb/libusb/wiki/Windows

it's only said that the device must have a GUID, but not whether I can
recycle it.

 

Thanks in advance

 

 

From: sch...@tw... [mailto:sch...@tw...] 
Sent: Freitag, 1. Dezember 2017 12:15
To: 'lib...@li...'
<lib...@li...>
Subject: Composite WinUSB interface claim fails

 

Hello There,

 

I'm looking for some help in developing a libusb-application.

 

I'm developing the Hardware as well as the software and require some more
understanding of the libusb.

I'm developing on WIN10.

 

My current situation is following:

I'm using a composite Device having winUSB attached to the first two
interfaces, using WCID. (Next two interfaces are CDC Devices)

They get reported as IF0/1 by USB tree Viewer.

So I have to open interface 0/1 with libusb?

The first attempt to open this device fails, as expected, because to being
the composite parent,

The second one succeeds.

 

Claiming Interface 1 works(my application and xusb report no error on this)

Claiming Interface 0 returns a -12(libusb_not_supported) error, xusb reports
6 Ifs being present(one more than expected)

And fails on all except Interface 1.

 

The Docs say that claiming is a purely logical operation, which means my
firmware does not have to do anything with it.

So I assume this is a Windows/libusb error I have to deal with.

 

I was using libusb 1.0.20 when I somewhen found out that the composite
device support is much better on 1.0.21.

Now I'm using the github Version, compiled with MSVC2015(was just compiling
fine - awesome)

 

Could you please give me advice on how I can get fixed this?

 

My current code is attached.

 

             bool deviceFound = false;

             int i = -1;

             

             while ((deviceFound == false) && ( (++i) < numDevices))

             {

                    dev = usbDevices[i];

                    libusb_get_device_descriptor(dev, &desc);

 

                    

                    if ((desc.idVendor == TIVA_USB_VID) & (desc.idProduct ==
TIVA_USB_PID)) {

                           //Found some candidate;

                           int tst = libusb_open(dev, &m_pUSB);
//crashes, when being composite parent

 

                           if ( tst > -1) 

                           {

                                  if (m_pUSB != NULL )

                                  {

                                        deviceFound = true;

                                        this->setIdentifier(QString("XCD
Bulk Pipe"));

                                  }

                           }

 

                    }

             }//End of while loop

 

        if(usbDevices)

        {

            libusb_free_device_list(usbDevices, 1);

        }

    }

 

       //Make the device available to this applicatrion;

    if(!retValue.containsError())

    {

             int test = 0; //set default Configuration value;

             //detaching kernel drivers is mostly needed when interfaceing
to HID Devices(especially on MAC OS and Linux

           m_autoDetach  = (libusb_set_auto_detach_kernel_driver(m_pUSB, 1)
== LIBUSB_SUCCESS) ;       //Try setting Kernel detach;

 

             int val;

             status = libusb_get_configuration(m_pUSB, &val);

             status = libusb_set_configuration(m_pUSB, val);

 

             libusb_config_descriptor *config;

             status =
libusb_get_config_descriptor(libusb_get_device(m_pUSB), 0, &config);

             status = libusb_claim_interface(m_pUSB, TIVA_INTERFACE_NUMBER);
//               ->            FAILS ON IF0, SUCCEEDS on IF1

             if (status < 0) 

        {

                    retValue += ito::RetVal(ito::retError, status,
libusb_error_name(status));

             }

    }