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...
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