On Tue 30 July 2013 15:12:57 Ricardo Ribalda Delgado wrote: > Hello > > I am developing a driver for a camera that supports read/write and > mmap access to the buffers. > > When I am running the compliance test, I cannot pass it because of > this test on v4l2-test-formats.cpp > > 904 if (!(node->caps & V4L2_CAP_READWRITE)) > 905 fail_on_test(cap->readbuffers); > 906 else if (node->caps & V4L2_CAP_STREAMING) > 907 fail_on_test(!cap->readbuffers); > > What should be the value of cap-readbuffers for a driver such as mine, > that supports cap_readwrite and cap_streaming? Or I cannot support > both, although at least this drivers do the same? The readbuffers parameter is highly dubious. I generally set it in a driver to the lowest number of buffers the hardware allows (e.g. what VIDIOC_REQBUFS returns if you give it a buffer count of 1). In theory this value allows you to increase the number of buffers used by read() so you can have more frames pending. In practice the only driver using it is sn9c102, which is an obscure webcam that really should be folded into the gspca driver suite. I am really tempted to deprecate/obsolete readbuffers. Anyway, to squash this compliance error just set readbuffers to the lowest number of allowed buffers. Regards, Hans > > > $ git grep CAP_READWRITE * | grep CAP_STREAMING > pci/cx25821/cx25821-video.c: V4L2_CAP_READWRITE | V4L2_CAP_STREAMING; > pci/cx88/cx88-video.c: cap->device_caps = V4L2_CAP_READWRITE | > V4L2_CAP_STREAMING; > pci/saa7134/saa7134-video.c: cap->device_caps = V4L2_CAP_READWRITE | > V4L2_CAP_STREAMING; > platform/marvell-ccic/mcam-core.c: V4L2_CAP_READWRITE | V4L2_CAP_STREAMING; > platform/via-camera.c: V4L2_CAP_READWRITE | V4L2_CAP_STREAMING; > usb/cx231xx/cx231xx-video.c: cap->device_caps = V4L2_CAP_READWRITE | > V4L2_CAP_STREAMING; > usb/em28xx/em28xx-video.c: V4L2_CAP_READWRITE | V4L2_CAP_VIDEO_CAPTURE > | V4L2_CAP_STREAMING; > usb/stkwebcam/stk-webcam.c: | V4L2_CAP_READWRITE | V4L2_CAP_STREAMING; > usb/tlg2300/pd-video.c: V4L2_CAP_STREAMING | V4L2_CAP_READWRITE; > > > Thanks! > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
