Hi. First, sorry for non-threaded reply. I found the thread on gmane while googling a bit. I'll try to explain the design and intended use of python-libusb1 polling integration. I lack twisted knowledge to tell how it could be integrated, though. As for the "poller" interface, it's python's select.poll interface. Basically, libusb needs to be called into explicitly[1] whenever events needing some handling occur. It signals those events through a set of poll- able file descriptors[2]. Alternatively (for OSes which cannot poll arbitrary file descriptors), LibUSBContext.getNextTimeout can be used to know for how long app can sleep (or do its own business) before next libusb event handling time... But that only works when libusb calls (transfer submission, synchronous or not) are all done in a single thread, otherwise they might last too long. When several threads can simultaneously wait for events to occur (ex: a poller waiting on an asynchronous transfer with long timeout, then in a second thread a synchronous call expected to return quickly) a more complex scheme needs to be used. See libusb doc for the whole story. In short, I decided to just write a stand-alone polling thread to support multi-thread access, as I couldn't figure a pythonic way of supporting several concurrent libusb-oriented pollers: C API relies on a mutable boolean-ish set by libusb code, and read by application code. As I try to never expose ctype instances to application code, and thought it should be enough to provide module user with a "start once, then forget" thread for handling this (much easier in python than in C), I went that way. Besides the functions working with that boolean, I exposed all needed methods on LibUSBContext class, so different implementations can be done without hacking/working around, and hopefully without using libusb1 module directly (except for symbolic constants). I am opened to suggestions on how to expose the few missing functions in a pythonic way. [1] LibUSBContext.handleEvents & co. [2] LibUSBContext.getPollFDList, LibUSBContext.setPollFDNotifiers Regards, -- Vincent Pelletier