When I tried to modified the code like this:
for dev in usb_devs:
print dev
dev.set_configuration()
print 'Vendor:',dev.idVendor
print 'Product:',dev.idProduct
print 'Manufacturer:',getStringDescriptor(dev,1)
print
'Manufacturer:',dev._ctx.backend.get_string_descriptor_ascii(dev._ctx.handle,dev.iManufacturer)
The dev.set_configuration() itself also raised the :
usb.core.USBError: Operation not supported or unimplemented on this platform
2010/9/10 Gao Hong <joy.highl...@gmail.com>
> Sorry,Can you make it clear,where to add the dev.set_configuration() code?
>
> The set_configuration function self also need a device_handle which is
> obtained from the open_device() function.
>
> Now it seems that the device has already been opened?
>
> 2010/9/10 Wander Lairson <wander.lair...@gmail.com>
>
>> 2010/9/10 Gao Hong <joy.highl...@gmail.com>:
>> > I'm glad you reply so quickly,thanks for you advise.
>> > The prototype is already setup in the function _setup_prototypes
>> > like this:
>> >>
>> >> # int libusb_get_string_descriptor_ascii(libusb_device_handle *dev,
>> >>
>> >> # uint8_t desc_index,
>> >>
>> >> # unsigned char *data,
>> >>
>> >> # int length)
>> >>
>> >> lib.libusb_get_string_descriptor_ascii.argtypes = [
>> >>
>> >> _libusb_device_handle,
>> >>
>> >> c_uint8,
>> >>
>> >> POINTER(c_ubyte),
>> >>
>> >> c_int
>> >>
>> >> ]
>> >
>> > So,this is not the point where the error leads to.
>> > Frankly speaking,I knew nothing about the ctypes,and almost forget
>> > everything about the the C/C++ programming,the low level debug or C
>> > programming is too hard for me....
>> > Here is my script:
>> >>
>> >> import usb.core
>> >
>> > def InterfaceFilter(dev,ItfClass = 8):
>> >
>> > """"""
>> >
>> > try:
>> >
>> > for cfg in dev:
>> >
>> > try:
>> >
>> > inners = usb.util.find_descriptor(cfg,find_all = True)
>> >
>> > for inner in inners:
>> >
>> > if type(inner) == usb.core.Interface:
>> >
>> > print 'dev:%s:%s' % (dev,inner.bInterfaceClass)
>> >
>> > return inner.bInterfaceClass == ItfClass
>> >
>> > except:
>> >
>> > False
>> >
>> > except:
>> >
>> > False
>> >
>> > usb_devs = usb.core.find(find_all = True,custom_match = InterfaceFilter)
>> >
>> > print usb_devs
>> >
>> > for dev in usb_devs:
>> >
>> > print dev
>> >
>> > print 'Vendor:',dev.idVendor
>> >
>> > print 'Product:',dev.idProduct
>>
>> Ah, now I see what's the problem, internally PyUSB manages device
>> opening automatically. Try a call to set_configuration at
>> this point of the code:
>>
>> dev.set_configuration()
>>
>> Only to force device opening...
>>
>> >
>> > print
>> >
>> 'Manufacturer:',dev._ctx.backend.get_string_descriptor_ascii(dev._ctx.handle,dev.iManufacturer)
>> >
>> > This is the funcition I added to the libusb10.py Class _LibUSB:
>> >>
>> >> @methodtrace(_logger)
>> >>
>> >>
>> >>
>> #----------------------------------------------------------------------
>> >>
>> >> def get_string_descriptor_ascii(self,dev_handle,desc_index):
>> >>
>> >> """Added by GaoHong"""
>> >>
>> >> buffer = array.array('B','\x00' * 255)
>> >>
>> >> address, length = buffer.buffer_info()
>> >>
>> >>
>> >>
>>
>> _check(_lib.libusb_get_string_descriptor_ascii(dev_handle,desc_index,cast(address,
>> >> POINTER(c_ubyte)),length))
>> >>
>> >> return data
>> >
>> > I really not know what to do....
>> > P.S the code of :
>> >>
>> >> def getStringDescriptor(device, index):
>> >>
>> >> """
>> >>
>> >> """
>> >>
>> >> response = device.ctrl_transfer(usb.util.ENDPOINT_IN,
>> >>
>> >> usb.legacy.REQ_GET_DESCRIPTOR,
>> >>
>> >> (usb.util.DESC_TYPE_STRING << 8) |
>> >> index,
>> >>
>> >> 0, # language id
>> >>
>> >> 255) # length
>> >>
>> >> # TODO: Refer to 'libusb_get_string_descriptor_ascii' for error
>> >> handling
>> >>
>> >>
>> >>
>> >> return response[2:].tostring().decode('utf-16')
>> >
>> > Doesn't work on windows7 ,libusb windows backend, raise not implemtented
>> > error,I don't know why/
>> > 2010/9/10 Wander Lairson <wander.lair...@gmail.com>
>> >>
>> >> > Hello wander.lairson:
>> >> > First of all,thanks for your contribution for
>> >> > the opensource community
>> >> > and the work for libusb, I appricate it very much.
>> >> > Currently I want to fetch the serial number of the massive
>> storage
>> >> > device,which need the string descriptor. Unfortunately,the python
>> >> > interface
>> >> > hasn't wrapped the API yet. I tried to implement it myself and copy
>> some
>> >> > of
>> >> > the __read function code. Like this:
>> >> >>
>> >> >> def get_string_descriptor_ascii(self,dev_handle,desc_index):
>> >> >>
>> >> >> """Added by GaoHong"""
>> >> >>
>> >> >> buffer = array.array('B','\x00' * 255)
>> >> >>
>> >> >> address, length = buffer.buffer_info()
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>>
>> _check(_lib.libusb_get_string_descriptor_ascii(dev_handle,desc_index,cast(address,
>> >> >> POINTER(c_ubyte)),length))
>> >>
>> >> I am not sure if it is the problem (because I don't know how ctypes
>> >> pushes arguments in the stack), but if you haven't supplied the
>> >> function prototype, desc_index will be treated as an integer instead
>> >> of a 8 bits variable (as in the libusb_get_string_descriptor_ascii
>> >> interface). You might try this to see if it is a problem:
>> >>
>> >>
>> >>
>> _check(_lib.libusb_get_string_descriptor_ascii(dev_handle,c_uint8(desc_index),cast(address,POINTER(c_ubyte)),length))
>> >>
>> >> If not, I am affraid you will have to play with WinDBG to see what's
>> >> going on. Also, try to write a little C program that call
>> >> libusb_get_string_descriptor_ascii. I may cut off the possiblity of a
>> >> bug in libusb.
>> >>
>> >> PS: I could debug it for you, but currently I do have no free time for
>> >> it, I am really sorry.
>> >>
>> >> >>
>> >> >> return data
>> >> >
>> >> > but the result always raise WindowsError: exception: access violation
>> >> > reading 0x00000010
>> >> > File "E:\my_doc\My Dev\python\GWP 0902\usb_finder.py", line 60, in
>> >> > <module>
>> >> > print
>> >> >
>> >> >
>> 'Manufacturer:',back.get_string_descriptor_ascii(dev._ctx.handle,dev.iManufacturer)
>> >> > File "D:\Python26\Lib\site-packages\usb\_debug.py", line 53, in
>> do_trace
>> >> > return f(*args, **named_args)
>> >> > File "D:\Python26\Lib\site-packages\usb\backend\libusb10.py", line
>> 593,
>> >> > in
>> >> > get_string_descriptor_ascii
>> >> >
>> >> >
>>
>> _check(_lib.libusb_get_string_descriptor_ascii(dev_handle,desc_index,cast(address,
>> >> > POINTER(c_ubyte)),length-1))
>> >> > I don't know why,the only difference from __read function:
>> >> >>
>> >> >> def __read(self, fn, dev_handle, ep, intf, size, timeout):
>> >> >>
>> >> >> buffer = array.array('B', '\x00' * size)
>> >> >>
>> >> >> address, length = buffer.buffer_info()
>> >> >>
>> >> >> transferred = c_int()
>> >> >>
>> >> >> _check(fn(dev_handle,
>> >> >>
>> >> >> ep,
>> >> >>
>> >> >> cast(address, POINTER(c_ubyte)),
>> >> >>
>> >> >> length,
>> >> >>
>> >> >> byref(transferred),
>> >> >>
>> >> >> timeout))
>> >> >>
>> >> >> return buffer[:transferred.value]
>> >> >
>> >> > is the called function.
>> >> > Can you tell me why? Thank you very much.
>> >> > --
>> >> > It's a long journey to go! :-)
>> >> > Legend since 1985...
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Best Regards,
>> >> Wander Lairson Costa
>> >
>> >
>> >
>> > --
>> > It's a long journey to go! :-)
>> > Legend since 1985...
>> >
>>
>>
>>
>> --
>> Best Regards,
>> Wander Lairson Costa
>>
>
>
>
> --
> It's a long journey to go! :-)
> Legend since 1985...
>
--
It's a long journey to go! :-)
Legend since 1985...
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