Hi, Rail Shafigulin <rail@xxxxxxxxxxxxxxx> writes: >>>>> Let me apologize for emailing directly to the list as I'm not one of >>>>> the developers and just starting out with USB and UVC. After searching >>>> >>>> the list is open to anybody and we welcome newcomers :-) >>>> >>>>> online for about a week I just couldn't find answers and I hope the >>>>> original authors of the uvc-gadget tool are on the list and can help >>>>> out. >>>>> >>>>> Needed to test a UVC in a custom built kernel (Xilinx petalinux), . >>>>> Followed these directions, >>>>> https://github.com/torvalds/linux/blob/ef954844c7ace62f773f4f23e28d2d915adc419f/Documentation/usb/gadget-testing.txt#L717-L730. >>>>> >>>>> Patches didn't work. Had to look around for correct ones. Found them >>>>> here, http://markmail.org/message/hb7evzvigbuxptz5#query:+page:1+mid:s73fdeffjgb2v2yw+state:results. >>>>> >>>>> Combined and applied the patches into a repo here, >>>>> https://github.com/cyboflash/uvc-gadget.git. >>>>> >>>>> When I ran a test command, given in the instructions above, >>>>> uvc-gadget -u /dev/video<uvc video node #> -v /dev/video<vivid video node #> >>>>> >>>>> got the following error: >>>>> V4L2_CORE: (jpeg decoder) error while decoding frame >>>>> >>>>> and a black screen. >>>>> >>>>> One thing to note is that I was not using luvcview, but guvcview. >>>>> >>>>> It looks like the error is coming from here, >>>>> https://sourceforge.net/p/guvcview/git-master/ci/master/tree/gview_v4l2core/jpeg_decoder.c#l1503 >>>>> >>>>> My thoughts >>>>> 1. I don't think the error is coming from v4l2. I tested it on another >>>>> machine and it worked. But I'm not an expert so I can't say for sure. >>>>> 2. I don't think the error is coming from UVC. I think since I see a >>>>> black screen, it is working. Again, I'm not an expert, so I can't say >>>>> for sure. >>>>> 3. I think the error is due to uvc-gadget test application. It could >>>>> be that the applied patches are outdated, but I just didn't find >>>>> anything else online. But, I'm not an expert so definitely can't say >>>>> for sure. >>>>> >>>>> I would greatly appreciate any help with this as I'm just starting out >>>>> with UVC and USB. >>>> >>>> Which kernel are you using? Which UDC driver are you using? >>> >>> Balbi, >>> >>> The board is configured as a USB Camera Gadget. Here is the output of uname -a >>> Linux Xilinx-ZCU102-2016_3 4.6.0 #33 SMP Thu Aug 10 11:47:57 PDT 2017 >>> aarch64 GNU/Linux >> >> okay, then you need to ask for support from whoever gave you this >> kernel. 4.6 is a really old release which this forum doesn't support. >> >>> When you say UDC (USB Device Controller) driver, what exactly do you mean? >> >> which driver is g_webcam binding to? What do you have under >> /sys/class/udc ? > > I have this under /sys/class/udc > > fe200000.dwc3 > > under /sys/class/udc/fe200000.dwc3 okay. Test against mainline and I can help you; otherwise you need to go after Xilinx or whoever gave you this v4.6 kernel. -- balbi
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