Re: [Libusbx-devel] libusb_open LIBUSB_ERROR_ACCESS problem

[Mohamed H. <req...@gm...>]

Hi,
I use libusb1.0.14/WinUSB (v6.1.7600.16385)
This is a simple program which can reproduce the problem (output is in
the last) :

#include <stdio.h>
#include "libusb.h"


struct device_descriptor {
uint16_t vid;
uint16_t pid;
};

static struct device_descriptor managed_devices[] = {
{ 0x0525, 0xA4A0 },
};

int main(int argc, char* argv[])
{
libusb_device **devs;
int r, card_count = 0;
ssize_t cnt;
libusb_device *dev;
int i = 0;
libusb_context* context;
libusb_device_handle* handle1, *handle2;
r = libusb_init(&context);
if (r < 0)
return r;
libusb_set_debug(context, 3);
cnt = libusb_get_device_list(context, &devs);
if (cnt < 0)
return (int) cnt;

while ((dev = devs[i++]) != NULL) {
struct libusb_device_descriptor desc;
int r = libusb_get_device_descriptor(dev, &desc);
if (r < 0) {
fprintf(stderr, "failed to get device descriptor");
return -1;
}
printf("%04x:%04x (bus %d, device %d)\n",
desc.idVendor, desc.idProduct,
libusb_get_bus_number(dev), libusb_get_device_address(dev));
if((managed_devices[0].vid == desc.idVendor) &&
(managed_devices[0].pid == desc.idProduct)){
card_count++;
break;
}
}
/*first open*/
r = libusb_open(dev, &handle1);
Sleep(1000);
/*first close*/
libusb_close(handle1);
Sleep(1000);
/*second open : failed -3*/
r = libusb_open(dev, &handle2); /* here i have always -3 error in return code */
Sleep(1000);
if(!r)
libusb_close(handle2);

libusb_free_device_list(devs, 1);

libusb_exit(context);
return 0;
}
/*output of the program */
/* 8086:27c9 (bus 3, device 1)
8086:27cb (bus 5, device 1)
8086:27c8 (bus 2, device 1)
8086:27ca (bus 4, device 1)
1414:0004 (bus 1, device 1)
8086:27cc (bus 6, device 1)
0461:4d81 (bus 4, device 2)
0525:a4a0 (bus 6, device 3)
libusbx: error [winusbx_open] could not open device
\\.\USB#VID_0525&PID_A4A0#1_00000000#{A5DCBF10-6530-11D2-901F-00C04FB951ED}
(interface 0): [5] Access denied */

Regards,
Mohamed

On Wed, Jan 2, 2013 at 7:16 AM, Xiaofan Chen <xia...@gm...> wrote:
> On Tue, Jan 1, 2013 at 8:21 PM, Mohamed HAMZAOUI <req...@gm...> wrote:
>> I have just describe for you the summary of the sequence of actions in
>> a large program ...
>
> Could you reproduce the issue with a simpler program and post
> the debug log?
>
>> There are various purposes for which you can open and close a dev and
>> then open it another time... (managing licenses saved on the card in
>> my case...), but in general there is no restriction on the
>> documentation !
>
> This should be okay. It would be good if you can post more
> debug logs to help debug the issue.
>
> BTW, do you have libusbK installed in your system? Are you
> using WinUSB driver or other driver? Just want to get rid of more
> variables.
>
> --
> Xiaofan
>
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