libusb basic example wanted

Question

I'm writing user-space program that is intended to control some device via usb so I decided to use libusb (libusb-1.0) to send control messages to and receive responses from that device.

But I constantly receive the following bunch of errors from my code (even when it's executed using 'sudo'):

USB error: could not set config 0: Device or resource busy
set configuration: failed
Check that you have permissions to write to 007/012 and, if you don't, that you set up hotplug (http://linux-hotplug.sourceforge.net/) correctly.
USB error: could not claim interface 0: Device or resource busy
claim interface: failed
USB error: error submitting URB: No such file or directory
bulk writing: failed
USB error: error submitting URB: No such file or directory
bulk reading: failed
response was: 

The code is:

usb_dev_handle* find_device ();

int 
main (int argc, char *argv[])
{
    usb_dev_handle* udev;
    int status;
    char request[] = "K1"; // 'ping' command used to check communication
    char response[256];

    udev = find_device ();
    // udev is successfully found here

    status = usb_set_configuration (udev, 0);
    printf ("set configuration: %s\n", status ? "failed" : "passed");

    status = usb_claim_interface (udev, 0);
    printf ("claim interface: %s\n", status ? "failed" : "passed");

    status = usb_bulk_write (udev, 3, request, sizeof (request), 500);
    printf ("bulk writing: %s\n", status ? "failed" : "passed");

    status = usb_bulk_read (udev, 2, response, sizeof (response), 500);
    printf ("bulk reading: %s\n", status ? "failed" : "passed");

    printf ("response was: %s\n", response);

    usb_close (udev);

    return 0;
}

What's wrong with the code? And how it could be fixed?

OS: Ubuntu 10.10

Answer 1

Answering this question as I had faced this issue on the same OS and was able to solve in the following manner:

Download and Compile the latest libusb source code 1.0.8.

Following are some API calls that I used in order to claim USB interface 0:

libusb_init(NULL);
libusb_open_device_with_vid_pid(NULL, vendor_id, product_id);
libusb_detach_kernel_driver(devh, 0);
libusb_claim_interface(devh, 0);
libusb_close(devh);
libusb_exit(NULL);

Description of the variables in the above example:

static struct libusb_device_handle *devh = NULL;
uint16_t vendor_id;
uint16_t product_id;

To get the vendor ID and product ID, you may run the following commands (Ex. my device info)

$ lsusb
...
Bus 001 Device 013: ID 0930:6544 Toshiba Corp. Kingston DataTraveler 2.0 Stick (2GB)
...

The bold colon delimited string contains vendor and product id respectively.

How to compile the code:

I used the following command to compile my code:

/bin/bash libtool --silent --tag=CC --mode=link g++ -Wall -Wundef -Wunused -Wshadow -D_DEBUG -I../libusb -g -O2 -o read read.cpp ../libusb/libusb-1.0.la -lusb-1.0 -lrt

Copy libtool to the compilation area from the extracted libusb-1.0.8 directory.

Hope this helps.