Hi,
i am too sorry. Having searched half the evening a few seconds after asking my
question i found the "Specifying libraries by hand" section in the manual.
And indeed this:
>>> import usb.core
>>> import usb.backend.libusb1
>>>
>>> backend = usb.backend.libusb1.get_backend(find_library=lambda x: "/
usr/lib/libusb-1.0.so")
>>> dev = usb.core.find(..., backend=backend)
Solves my problem!!
Sorry for asking too early!
Till
On Sunday, March 20, 2016 12:10:49 PM Till Harbaum wrote:
> Hi,
>
> i am trying to use pyusb on a buildroot based embedded setup running on a ti
> sitara. But i struggle to get it to recognize a backend:
>
> # python
> Python 2.7.11 (default, Mar 19 2016, 14:18:04)
> [GCC 5.2.1 20151005] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>
> >>> import os
> >>> os.environ['PYUSB_DEBUG'] = 'debug'
> >>> import usb.core
> >>> usb.core.find()
>
> 2016-03-19 22:11:46,002 ERROR:usb.libloader:'Libusb 1' could not be found
> 2016-03-19 22:11:46,013 ERROR:usb.backend.libusb1:Error loading libusb 1.0
> backend
> 2016-03-19 22:11:46,079 ERROR:usb.libloader:'OpenUSB library' could not be
> found
> 2016-03-19 22:11:46,089 ERROR:usb.backend.openusb:Error loading OpenUSB
> backend
> 2016-03-19 22:11:46,258 ERROR:usb.libloader:'Libusb 0' could not be found
> 2016-03-19 22:11:46,268 ERROR:usb.backend.libusb0:Error loading libusb 0.1
> backend
>
> The shared libs are there:
> # ls -la /usr/lib/libusb*
> lrwxrwxrwx 1 root root 19 Mar 19 14:51 /usr/lib/
> libusb-0.1.so.4 -> libusb-0.1.so.4.4.4
> -rwxr-xr-x 1 root root 10872 Mar 19 15:17 /usr/lib/
> libusb-0.1.so.4.4.4
> lrwxrwxrwx 1 root root 19 Mar 19 14:20 /usr/lib/
> libusb-1.0.so -> libusb-1.0.so.0.1.0
> lrwxrwxrwx 1 root root 19 Mar 19 14:20 /usr/lib/
> libusb-1.0.so.0 -> libusb-1.0.so.0.1.0
> -rwxr-xr-x 1 root root 57400 Mar 19 15:17 /usr/lib/
> libusb-1.0.so.0.1.0
> lrwxrwxrwx 1 root root 19 Mar 19 14:51 /usr/lib/libusb.so
> -> libusb-0.1.so.4.4.4
>
> Now i am missing the bridge between pyusb and those shared libs.
>
> How can i debug further? I tried stracing the whole setup but i don't see it
> even trying to open any library. How exaclty is pyusb trying to open those
> libraries. Under which paths and which names is it supposed to search?
>
> Thanks,
> Till
--
Dr. Till Harbaum <t...@harbaum.org>
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