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 be that the applied patches are outdated, but I just didn't find 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
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