On Tue, Jun 30, 2015 at 8:23 AM, Jayan John <jayanjohn79@xxxxxxxxx> wrote: > On Tue, Jun 30, 2015 at 6:50 AM, Peter Chen <Peter.Chen@xxxxxxxxxxxxx> wrote: >> >>> On Tue, Jun 30, 2015 at 12:33 AM, Steve Calfee <stevecalfee@xxxxxxxxx> >>> wrote: >>> > On Mon, Jun 29, 2015 at 7:16 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> >>> wrote: >>> >> On Mon, 29 Jun 2015, Peter Chen wrote: >>> >> >>> >>> Just like Steve pointed, it should be a ZLT problem, do you have >>> >>> below patch in your tree, and the host may not send zlt, but you may >>> >>> queue an zero-length request, the f_hid does not set req->zero flag >>> >>> either. >>> >>> >>> >>> commit 953c66469735aed8d2ada639a72b150f01dae605 >>> >>> Author: Abbas Raza <Abbas_Raza@xxxxxxxxxx> >>> >>> Date: Thu Jul 17 19:34:31 2014 +0800 >>> >>> >>> >>> usb: chipidea: udc: Disable auto ZLP generation on ep0 >>> >>> >>> >>> >>> >>> If it still has problem, send me apps if possible (with needed >>> >>> kernel patches). >>> >> >>> >> Note that a UDC should _never_ queue an extra zero-length packet for >>> >> an OUT transfer, no matter how req->zero is set. In other words, >>> >> req->zero is supposed to affect only IN transfers. >>> >> >>> > Yes UDC gadgets receive packets sent by the host on OUT transfers. If >>> > ZLT transfers are needed for the protocol, a short transfer is needed >>> > to end an OUT sequence and it must be sent by the sender, in this case >>> > the host. The UDC should detect receiving a zero length EP0 OUT and >>> > that signals the end of the 64 byte transfer from host to gadget. >>> > >>> > Regards, Steve >>> >>> Thanks Alan, Peter and Steve for your help and quick response. >>> >>> In fact, today I tested with a similar patch i.e. have QH_IOS and QH_ZLT set for >>> control endpoint in udc.c. The 64 byte transfer appears to work fine. >>> >>> I am not sure whether this is the ideal solution, Testing some more to ensure >>> that there are no regressions. I will send out an update in about a day. >>> >> >> The most probably is the QH_ZLT bit, your tree may not the patch I mentioned >> above. The QH_IOS only affects a setup being received. >> >> Peter > > Sure, I will test this and update closure on this issue. > > Cheers, > Jayan The issue is resolved with the patch: commit 953c66469735aed8d2ada639a72b150f01dae605 Author: Abbas Raza <Abbas_Raza@xxxxxxxxxx> Thanks for all your support. -- 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
