On Mon, Dec 17, 2012 at 11:08 AM, Steve Calfee <stevecalfee@xxxxxxxxx> wrote: > On Mon, Dec 17, 2012 at 7:33 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> On Sun, 16 Dec 2012, Vincent Pelletier wrote: >> >>> Le dimanche 16 décembre 2012 20:46:38, Vincent Pelletier a écrit : >>> > I checked the specs, and the warnings about wMaxPacketSize seem >>> > justified (although it's unclear to me wether wMaxPacketSize is >>> > restricted to exactly 512B in HS, or only upper-bound at 512B). >>> >>> Another reply to myself: >>> Tested USB device uses a Cypress FX2LP: >>> >>> http://www.summitsoftconsulting.com/picts/iti_pcb_top.jpg >>> >>> I checked the FX2LP specs, and endpoint 1 in both directions is hardwired to >>> wMaxPacketSize of 64. I believe the FX2LP is quite widespread (judging by the >>> availability of a GPL toolchain for it and two CLI tools to send its >>> firmware), so those warnings might cause redundant bug reports. >> >> It does seem odd that people would buy and use these chips even >> though they are explicitly in violation of the USB specification. A >> device containing one of these things could never pass the USB-CV >> verification test. >> >> It may be possible for xhci-hcd to work around the bug (by internally >> changing wMaxPacketSize to 512). >> > > It does not need to be worked around. The fx2 docs specifically say > ep1 cannot be used as a bulk endpoint in HS mode. Vincent, RTFM, > Cypress has good, downloadable chip docs. Ep1 can either be a legal > int/iso endpoint or just not used - all specified in the > device/interface descriptors. Nothing in the USB spec requires all > device endpoints to be used, or that interfaces have sequentially > numbered endpoints. > > Regards, Steve Hi, Vincent, After reading the first message in the thread I realized that you are not writing the fx2 device, but are trying to use a device you purchased. Sorry. The fx2 is not at fault, the device has a bad, invalid endpoint descriptor for ep1. I doubt if they are using the ep, just defining it. Perhaps you could contact the manufacturer? Regards, Steve -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
