Wander Lairson Costa wrote: > I am trying to do a isochronous loop transfer, I can write the data > but I am getting an error when trying to read it. Following are the > logs:
Isochronous endpoints have peculiar rules for reading. Each packet in an isochronous transfer maps to one microframe in real time. It's not like a bulk or interrupt transfer where it just hangs around until it's full. If you have 8 packets in your transfer, you'll cover 8 microframes. If the device doesn't send anything in one of those microframes, you'll get zero bytes back for that packet. The endpoint packet size is 32 (in the header), and your request is for 128 bytes, so you should be covering 4 microframes. It's quite normal for one of those packets to fail when the other ones succeed. That what it looks like here -- packet 0 failed, but the other three did not. Error -71 is EPROTO, suggesting a protocol violation. I guess that implicates the firmware. Have you done an lsusb to make sure the descriptors match what you expect? -- Tim Roberts, t...@probo.com Providenza & Boekelheide, Inc. ------------------------------------------------------------------------------ Master HTML5, CSS3, ASP.NET, MVC, AJAX, Knockout.js, Web API and much more. Get web development skills now with LearnDevNow - 350+ hours of step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122812 _______________________________________________ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
