2012/2/8 Braiden Kindt <brai...@braiden.org>: > PyUSB raises timeout after reading non-zero amount of data from bulk endpoint > > libusb_bulk_transfer may return both a non-zero transferred size and > also an errno indicating timeout. > > In such cases, pyusb raises an exception, and there's no way for my > application to retrieved the data that was read from USB. As a result, > the data is lost. Subsequent reads will not return it. > > See libusb-1.0 docs: > http://libusb.sourceforge.net/api-1.0/group__syncio.html#gab8ae853ab492c22d707241dc26c8a805 > ...check transferred when dealing with a timeout error code. libusb > may have to split your transfer into a number of chunks to satisfy > underlying O/S requirements, meaning that the timeout may expire after > the first few chunks have completed. libusb is careful not to lose any > data that may have been transferred; do not assume that timeout > conditions indicate a complete lack of I/O. >
Thanks for the report. > You can pull my my patched version here: > git://github.com/braiden/pyusb.git (up-to-date with your master > branch) > > I've been using this for a couple weeks without issue. Patch is pretty > trivial. in libusb10, don't call _check unless zero bytes transferred. > I've only seen the issue while reading from device, but I assume it > possible on write too. And thanks for the patch. I will apply it asap. > > I think the issue applies to libusb01 too. > Would mind trying to confirm it? I will check the docs, but if you can reproduce it (either with legacy libusb or with libusb-compat) is better. > I can pretty reliably reproduce issue. Let me know if I can provide > more detail or help verify fix. > After I apply the patch I might ask you to re-test. -- Best Regards, Wander Lairson Costa ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ pyusb-users mailing list pyusb-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pyusb-users
