2014-07-31 14:48 GMT-03:00 Samuel Thurston <samuel-thurs...@uiowa.edu>:
>
> On 07/30/2014 05:51 PM, Wander Lairson Costa wrote:
>> 2014-07-30 15:01 GMT-03:00 Samuel Thurston <samuel-thurs...@uiowa.edu>:
>>> Hello all,
>>>
>>> I'm trying to use pyusb on an embedded yocto linux running on an intel
>>> Galileo board.  I'm running into problems trying to load the custom
>>> backend as specified in the tutorial page.  Since there is no compile
>>> environment I'm missing ldconfig.  When I go to get a handle to the
>>> device the "normal way" I get this error:
>>>
>>>   >>> dev = usb.core.find(idVendor = vid, idProduct = pid)
>>> Traceback (most recent call last):
>>>     File "<stdin>", line 1, in <module>
>>>     File "/usr/lib/python2.7/site-packages/usb/core.py", line 864, in find
>>>       raise ValueError('No backend available')
>>> ValueError: No backend available
>>>
>>> I located the library to link at /lib/libusb-1.0.so.0
>>>
>>> so I tried to use the method described to specify a "find_library" function.
>>>
>>>
>>>   >>>
>>>   >>> backend = usb.backend.libusb1.get_backend(find_library=lambda x:
>>> "/lib/libusb-1.0.so.0")
>>> Traceback (most recent call last):
>>>     File "<stdin>", line 1, in <module>
>>> TypeError: get_backend() takes no arguments (1 given)
>>>
>>>
>>> I don't really understand the mechanism at play here, so I don't have
>>> any ideas for next steps.  If anyone can provide some guidance I'd be
>>> very grateful.
>>>
>>> for what it's worth, here's the DATA section from help(usb)
>>>
>>> DATA
>>>       __all__ = ['legacy', 'core', 'backend', 'util']
>>>       __author__ = 'Wander Lairson Costa'
>>>       __version__ = '1.0.0b1'
>>>
>>>
>> Hmm, unfortunately this feature is not available on any tagged version
>> yet. Could you please test with [1] ?
>>
>> [1] https://github.com/walac/pyusb/tarball/master
>>
> That worked perfectly.  My only remark is that the tarball is labelled
> 1.0.0b1 but the installed version is listed as 1.0.0b2.
>

That's because I didn't tag b2 yet.

> Thanks very much for the fix!
>

You're welcome.


-- 
Best Regards,
Wander Lairson Costa

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