Re: [pyusb-users] Error doing control transfer

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libusb 1.0 is loading from here 'C:\openocd-0.7.0\bin\libusb-1.0.dll'.

Aww man. I never looked at it that carefully.
If you had not pointed that out, I wouldn't have tried myself to find the
reason behind it not working.

Lesson Learned: Debug Logs are IMPORTANT! and DESERVE A CONSCIOUS READ.

Thanks a ton
Vivek

On Fri, Oct 4, 2013 at 12:03 AM, vvyogi . <vv...@gm...> wrote:

> Again, Out of curiosity I was browsing through the *
> "C:\Python27\Lib\site-packages" *directory, and there was backend
> subdirectory inside the usb directory. And it had
> 1. libusb0.py
> 2. libusb1.py
> 3. openusb.py
>
> I quickly ran this code( as suggested by you(Wander Liarson) earlier):
>
>  import usb.backend.libusb0
>> b = usb.backend.libusb0.get_backend()
>> dev = usb.core.find(backend=b, idVendor=5824, idProduct=1503)
>>
>> # was it found?
>> if dev is None:
>>     raise ValueError('Device not found')
>>
>> print "VUSB Device Found"
>> print dev.bNumConfigurations
>> print dev.bDeviceClass
>> print dev.bLength
>> # set the active configuration. With no arguments, the first
>> # configuration will be the active one
>> dev.set_configuration()
>> dev.ret = dev.ctrl_transfer(0xC0, 0x00, 0, 0, 128)
>>
>
> AND ITS DONE !
> Its finally WORKING ! Awesome.
>
>
> Thanks and Regards
> Vivek
>
>
> On Thu, Oct 3, 2013 at 11:54 PM, vvyogi . <vv...@gm...> wrote:
>
>>  Try to put it in C:\Python27
>>>
>> That made no difference.
>>
>> Out of curiosity, I removed the dll from System32 directory and yet pyUsb
>> didn't complained anything. This inspires me to ask "Where exactly is
>> pyUsb's backend? Which dll is it using?"
>>
>> And Finally, I wiped out the python distribution completely and tried
>> with a fresh install. I installed only pyUSB( master branch from github )
>> Log seems to be changed:
>>
>>  2013-10-03 23:44:23,200
>>> DEBUG:usb.backend.libusb1:_LibUSB.__init__(<WinDLL
>>> 'C:\openocd-0.7.0\bin\libusb-1.0.dll', handle 6b600000 at 1804490>)
>>> 2013-10-03 23:44:23,201 INFO:usb.core:find(): using backend
>>> "usb.backend.libusb1"
>>> 2013-10-03 23:44:23,203
>>> DEBUG:usb.backend.libusb1:_LibUSB.enumerate_devices()
>>> 2013-10-03 23:44:23,263
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A5630>)
>>> 2013-10-03 23:44:23,263
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A56D0>)
>>> 2013-10-03 23:44:23,263
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A5690>)
>>> 2013-10-03 23:44:23,263
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A56F0>)
>>> 2013-10-03 23:44:23,265
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A5630>)
>>> 2013-10-03 23:44:23,265
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A56D0>)
>>> 2013-10-03 23:44:23,265
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_device_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A5690>)
>>> 2013-10-03 23:44:23,265
>>> DEBUG:usb.backend.libusb1:_LibUSB.get_configuration_descriptor(<usb.backend.libusb1._Device
>>> object at 0x018A5690>, 0)
>>> 2013-10-03 23:44:23,266
>>> DEBUG:usb.backend.libusb1:_LibUSB.open_device(<usb.backend.libusb1._Device
>>> object at 0x018A5690>)
>>> 2013-10-03 23:44:23,266
>>> DEBUG:usb.backend.libusb1:_LibUSB.set_configuration(<usb.backend.libusb1._DeviceHandle
>>> object at 0x01776930>, 1)
>>>
>>> VUSB_HID Device Found
>>> 1
>>> 255
>>> 18
>>> Traceback (most recent call last):
>>>   File "myu.py", line 24, in <module>
>>>     dev.set_configuration()
>>>   File "C:\Python27\lib\site-packages\usb\core.py", line 559, in
>>> set_configuration
>>>
>>>     self._ctx.managed_set_configuration(self, configuration)
>>>   File "C:\Python27\lib\site-packages\usb\core.py", line 92, in
>>> managed_set_configuration
>>>     self.backend.set_configuration(self.handle, cfg.bConfigurationValue)
>>>   File "C:\Python27\lib\site-packages\usb\_debug.py", line 60, in
>>> do_trace
>>>     return f(*args, **named_args)
>>>   File "C:\Python27\lib\site-packages\usb\backend\libusb1.py", line 741,
>>> in set_configuration
>>>     _check(self.lib.libusb_set_configuration(dev_handle.handle,
>>> config_value))
>>>   File "C:\Python27\lib\site-packages\usb\backend\libusb1.py", line 571,
>>> in _check
>>>
>>>     raise USBError(_str_error[ret], ret, _libusb_errno[ret])
>>> usb.core.USBError: [Errno 2] Entity not found
>>> 2013-10-03 23:44:23,285
>>> DEBUG:usb.backend.libusb1:_LibUSB.close_device(<usb.backend.libusb1._DeviceHandle
>>> object at 0x01776930>)
>>> 2013-10-03 23:44:23,285 DEBUG:usb.backend.libusb1:_LibUSB.__del__()
>>
>>
>> The error code is same "*[Errno 2] Entity not found*" however, pyUsb
>> seems to be using the libusb1 backend now.
>>
>> I don't really understand whats going on here. Is there anyway I can make
>> it work?
>>
>> Thanks and Regards
>> Vivek
>>
>>
>> On Thu, Oct 3, 2013 at 9:07 PM, Wander Lairson Costa <
>> wan...@gm...> wrote:
>>
>>> 2013/10/3 vvyogi . <vv...@gm...>:
>>> >> Python is not finding the libusb-win32.dll file, you could put it
>>> >>
>>> >> inside the python interpreter directory just for tests
>>> >
>>> >
>>> > The directory C:\Python27\DLLs contains libusb0.dll, this same file is
>>> also
>>> > there in C:\Windows\System32 directory.
>>> > I removed the dll from C:\Python27\DLLs and I ran my program, it gave
>>> the
>>> > same error log( as if removing the dll made no difference). Does this
>>> means
>>> > that pyUsb is using backend from system32(or I am looking at the wrong
>>> > directory).
>>>
>>> libusb 1.0 has higher priority when detecting which backend to use.
>>> That's because I told you to force it through the *backend* find
>>> parameter.
>>>
>>> [snip]
>>>
>>> >
>>> > Now about the libusb-win32.dll, I couldn't locate this dll.
>>> > In the libusb-win32 distribution there i a libusb0_x86.dll, is this the
>>> > required dll that I need to put in C:\Python27\DLLs ?
>>>
>>> My bad, I told you the name of the dll was libusb-win32.dll, it is
>>> actually libusb0.dll. Sorry.
>>>
>>> > Kindly suggest where to look for the dll and where to put it ?
>>> >
>>>
>>> Try to put it in C:\Python27
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Best Regards,
>>> Wander Lairson Costa
>>>
>>>
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>>
>>
>