Re: [pyusb-users] Help with ERROR please [usb.core.USBError: [Errno None] b'libusb0-dll:err [_usb_reap_async]

[Xiaofan C. <xia...@gm...>]

On Wed, Mar 8, 2017 at 9:22 PM, Greg Horler <dr....@gm...> wrote:
> Xiaofan,
>
> I have removed all devices filters using the libusb-win32.exe tool and I
> have not had a crash....yet.
>
> What is/was the purpose of the filter? A lay-man's answer would be good
> please.

For Windows driver it is rather complicated and no layman
answer will probably be available.

In general, you need to have a supported driver in order to use libusb-1.0
Windows and libusb-win32. Most of the cases you will need to switch
the driver from original vendor driver to the support driver.

libusb-win32 library (libusb0.dll): either libusb0.sys (device driver
or filter driver)
or libusbk.sys

libusb-1.0 Windows library (libusb-1.0.dll): either WinUSB.sys or
libusbK.sys (libusb0.sys is not working well, do not use it) or HID
or usbdk.

The filter driver is to enable libusb-win32 library (libusb0.dll)
to be used without replacing the existing vendor driver.

The current version of libusb-win32 device filter is in general safe to use.
It is just it may not work with some device. But it may not work with some
device (eg: those using UMDF driver).

usbdk may be a potential replacement for libusb-win32 filter driver.

In general, libusb-win32 is no longer recommended to be used
for new development. It is recommended to switch to libusb
(libusb-1.0 API).

Ref:
https://github.com/libusb/libusb/wiki/Windows
https://github.com/libusb/libusb/wiki/FAQ
https://sourceforge.net/p/libusb-win32/wiki/Home/


-- 
Xiaofan