Dne 2.3.2017 v 09:19 Roger Quadros napsal(a): > Petr, > > On 02/03/17 06:57, Petr Cvek wrote: >> Dne 2.3.2017 v 00:22 Laurent Pinchart napsal(a): >>> Hi Roger, >>> >>> On Wednesday 01 Mar 2017 17:09:51 Roger Quadros wrote: >>>> Hi, >>>> >>>> I'm no longer able to use g_webcam with uvc-gadget [1] since v4.9. Logs at >>>> the end. It looks like we're goofing up on the control endpoint. >>>> >>>> If I revert the following commit everything works fine. >>>> commit 4fbac5206afd01b717d4bdc58793d471f3391b4b >>>> Author: Petr Cvek <petr.cvek@xxxxxx> >>>> Date: Wed Aug 17 12:36:57 2016 +0200 >>>> >>>> usb: gadget: uvc: Add missing call for additional setup data >>>> >>>> Am I missing something on uvc-gadget side or is the commit really bad? >>>> From what I understand, uvc-gadget is responsible for sending response to >>>> UVC class specific requests on control endpoint in uvc_send_response() >>>> in uvc_v4l2.c. >>>> >>>> So the reported commit is sending a duplicate response with probably >>>> improper data. >>> >>> Yes, this looks very dubious to me. I think it should be reverted. My >>> apologies for not having caught the patch during review. >> >> Hi, >> >> Now I've watched all codepaths again and yeah it is probably wrong patch, sorry. >> >> But if the code path is really: >> >> uvc_function_setup() -> userspace setup -> ioctl UVCIOC_SEND_RESPONSE -> uvc_send_response() -> usb_ep_queue() -> uvc_function_ep0_complete() -> userspace data >> >> it seems the USB timeouts with my hardware (PXA27x UDC) but with my patch it gets response immediately. >> > > I hope you were running uvc-gadget application on the PXA27x. > > Just sending a response is not sufficient. It must send a response with proper data. > f_uvc itself doesn't know how to handle UVC class specific requests and has to > depend on the user space application to populate the data in the response. > Hi, Yeah it was on the PXA27x, but that callback is not working there, so I was mistaken the bug is in UVC and not in PXA27x UDC itself. Anyway I was using a newer (unofficial [1]) version of uvc-gadget, which already implements the most of the UVC requests. BTW Did you try to use a configfs method for your usb webcam application? There was a discussion [2] about removing legacy UDC stuff (g_webcam and others g_*) in the future. If you used it, does it create these files for you? streaming_interval streaming_maxpacket streaming_maxburst P.S. Are you planning to use some generic linux friendly USB VID/PID? ;-) [1] https://github.com/madscientist42/uvc-gadget/commit/e127ec3a3022e1090b3b741b48f661670f5dade2 [2] http://www.spinics.net/lists/linux-usb/msg152678.html -- cheers, Petr -- 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
