Hi, Rail Shafigulin <rail@xxxxxxxxxxxxxxx> writes: >> 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 be that the applied patches are outdated, but I just didn't find 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 ? [...] > Here is what I do on my board: > > modprobe g_webcam > modprobe vivid [...] I'm assuming it's this "vivid" driver which isn't in the upstream kernel and, again, we can't support :-s If this is part of an SDK, you've probably already paid for support from the vendor, I suggest you use their support channel. Best of luck -- balbi
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