On Mon, Jun 2, 2014 at 8:22 PM, Xiaofan Chen <xiaofanc@xxxxxxxxx> wrote:
>
> My test code was not correct, and now I can reproduce your issue
> with either libusbk.sys or WinUSB.
>
> And you are also right without libusbk.dll and only use WinUSB,
> the test code will not fail.
>
> On the other hand, usually you should not need to
> open the device multiple times under libusb, you only
> need to do it once.
Here is the test code.
Mcuee@Win8X64VM /c/work/libftdi/test
$ cat testlibftdi.c
#include <stdio.h>
#include <stdlib.h>
#include <ftdi.h>
int main(void)
{
int i, ret;
for (i=0; i<50; i++) {
struct ftdi_context *dev = ftdi_new();
ftdi_set_interface(dev, INTERFACE_B);
fprintf(stderr, "opening device %d of 50...\n", i);
ret=ftdi_usb_open(dev, 0x0403, 0xcff8);
if(ret)
fprintf(stderr, "opening device failed\n");
ftdi_usb_close(dev);
ftdi_free(dev);
}
}
Here is the debug output. It seems to me there is a problem with
libusb Windows backend.
If possible, please help to translate the above program to pure libusb
(I am not a programmer myself) and reproduce the issue to confirm
that libftdi is not the problem.
$ export LIBUSB_DEBUG=2
With libusbK.dll
$ ./testlibftdi.exe
opening device 0 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
opening device 1 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
...
opening device 31 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0 (required to
claim 1 with WinUSB)
opening device 32 of 50...
libusb: warning [winusbx_claim_interface] failed to auto-claim
interface 0 (required to claim 1 with WinUSB): [84] Storage to process
this request is not available.
opening device failed
opening device 33 of 50...
libusb: warning [winusbx_claim_interface] failed to auto-claim
interface 0 (required to claim 1 with WinUSB): [84] Storage to process
this request is not available.
opening device failed
...
opening device 49 of 50...
libusb: warning [winusbx_claim_interface] failed to auto-claim
interface 0 (required to claim 1 with WinUSB): [84] Storage to process
this request is not available.
opening device failed
Without libusbK.dll
$ ./testlibftdi.exe
opening device 0 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
opening device 1 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
...
opening device 31 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
opening device 32 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
...
opening device 49 of 50...
libusb: warning [winusbx_claim_interface] auto-claimed interface 0
(required to claim 1 with WinUSB)
--
Xiaofan
--
libftdi - see http://www.intra2net.com/en/developer/libftdi for details.
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