Pyusb on Windows 7 - NotImplemented Error :is_kern

Question

I am using escposprinter python library for printing my data in thermal printer. It depends on pyusb. the library is working fine in linux . While in windows 7 ,i get the it have some issues. Here are output i get.

File "main.py", line 1, in <module>
    from app import app
  File "D:\freeth-in-erp-60ab8eb96fad\app\__init__.py", line 94, in <module>
    from .api_routes import *
  File "D:\freeth-in-erp-60ab8eb96fad\app\api_routes.py", line 44, in <module>
    from .printer import pos
  File "D:\freeth-in-erp-60ab8eb96fad\app\printer\pos.py", line 14, in <module>
    Epson = printer.Usb(idVendor=0x0416,idProduct=0x5011)
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\escposprinter\print
er.py", line 37, in __init__
    self.open()
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\escposprinter\print
er.py", line 46, in open
    if self.device.is_kernel_driver_active(0):
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\core.py", line
1064, in is_kernel_driver_active
    interface)
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\backend\__init_
_.py", line 365, in is_kernel_driver_active
    _not_implemented(self.is_kernel_driver_active)
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\backend\__init_
_.py", line 81, in _not_implemented
    raise NotImplementedError(func.__name__)
NotImplementedError: is_kernel_driver_active

i download the libusb-1.20 from libusb.info and copy file libusb-1.0.dll from MinGW32 and paste in "C:\windows\System32". I get the following result.

   from app import app
  File "D:\freeth-in-erp-60ab8eb96fad\app\__init__.py", line 94, in <module>
    from .api_routes import *
  File "D:\freeth-in-erp-60ab8eb96fad\app\api_routes.py", line 44, in <module>
    from .printer import pos
  File "D:\freeth-in-erp-60ab8eb96fad\app\printer\pos.py", line 14, in <module>
    Epson = printer.Usb(idVendor=0x0416,idProduct=0x5011)
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\escposprinter\print
er.py", line 37, in __init__
    self.open()
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\escposprinter\print
er.py", line 46, in open
    if self.device.is_kernel_driver_active(0):
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\core.py", line
1064, in is_kernel_driver_active
    interface)
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\backend\libusb1
.py", line 898, in is_kernel_driver_active
    intf)))
  File "D:\freeth-in-erp-60ab8eb96fad\venv\lib\site-packages\usb\backend\libusb1
.py", line 593, in _check
    raise NotImplementedError(_strerror(ret))
NotImplementedError: Operation not supported or unimplemented on this platform

my code is `

from escposprinter import *
from tabulate import tabulate

Epson = printer.Usb(0x0416,0x5011)

from library escposprinter

  class Usb(Escpos):
    """ Define USB printer """

    def __init__(self, idVendor, idProduct, interface=0, in_ep=0x82, out_ep=0x01):
        """
        @param idVendor  : Vendor ID
        @param idProduct : Product ID
        @param interface : USB device interface
        @param in_ep     : Input end point
        @param out_ep    : Output end point
        """
        self.idVendor  = idVendor
        self.idProduct = idProduct
        self.interface = interface
        self.in_ep     = in_ep
        self.out_ep    = out_ep
        self.open()


    def open(self):
        """ Search device on USB tree and set is as escpos device """
        self.device = usb.core.find(idVendor=self.idVendor, idProduct=self.idProduct)
        if self.device is None:
            print ("Cable isn't plugged in")

        if self.device.is_kernel_driver_active(0):
            try:
                self.device.detach_kernel_driver(0)
            except usb.core.USBError as e:
                print ("Could not detatch kernel driver: %s" % str(e))

help me with your suggestion `

Answer 1

The problem is plain and simple that the check whether a kernel driver is active which is not possible on Windows. It seems this library is simply not written for use on Windows.

You can use it on Windows if you delete the last 5 lines from the source code starting with if self.device.is_kernel_driver_active(0): or check if the code runs on Windows beforehand and don't call them.

Remember on Windows you need to install your own driver. I recommend using Zadig for creating and/or installing the driver.