Error In Ioctl Vidiocgmbuf
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returned by open().requestVIDIOC_QBUF, VIDIOC_DQBUFargpDescriptionApplications call the VIDIOC_QBUF ioctl to enqueue an empty (capturing) or filled (output) buffer in the driver's incoming queue. The semantics depend on the selected I/O method.To enqueue a buffer applications set the type field of a vidioc_dqbuf no such device struct v4l2_buffer to the same buffer type as was previously used with vidioc_streamon struct v4l2_format type and struct v4l2_requestbuffers type. Applications must also set the index field. Valid index numbers range from zero vidioc_querybuf to the number of buffers allocated with VIDIOC_REQBUFS (struct v4l2_requestbuffers count) minus one. The contents of the struct v4l2_buffer returned by a VIDIOC_QUERYBUF ioctl will do as well. When the buffer
V4l2_requestbuffers
is intended for output (type is V4L2_BUF_TYPE_VIDEO_OUTPUT, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, or V4L2_BUF_TYPE_VBI_OUTPUT) applications must also initialize the bytesused, field and timestamp fields, see the section called “Buffers” for details. Applications must also set flags to 0. The reserved2 and reserved fields must be set to 0. When using the multi-planar API, the m.planes field must contain a userspace pointer to a filled-in vidioc_reqbufs array of struct v4l2_plane and the length field must be set to the number of elements in that array. To enqueue a memory mapped buffer applications set the memory field to V4L2_MEMORY_MMAP. When VIDIOC_QBUF is called with a pointer to this structure the driver sets the V4L2_BUF_FLAG_MAPPED and V4L2_BUF_FLAG_QUEUED flags and clears the V4L2_BUF_FLAG_DONE flag in the flags field, or it returns an EINVAL error code.To enqueue a user pointer buffer applications set the memory field to V4L2_MEMORY_USERPTR, the m.userptr field to the address of the buffer and length to its size. When the multi-planar API is used, m.userptr and length members of the passed array of struct v4l2_plane have to be used instead. When VIDIOC_QBUF is called with a pointer to this structure the driver sets the V4L2_BUF_FLAG_QUEUED flag and clears the V4L2_BUF_FLAG_MAPPED and V4L2_BUF_FLAG_DONE flags in the flags field, or it returns an error code. This ioctl locks the memory pages of the buffer in physical memory, they cannot be swapped out to disk. Buffers remain locked until dequeued, until the VIDIOC_STREAMOFF or VIDIOC_REQBUFS ioctl is
Sign in Pricing Blog Support Search GitHub This repository Watch 17 Star 46 Fork 27 TheImagingSource/tiscamera Code Issues 14 Pull requests 1 Projects v4l2_memory_userptr 0 Wiki Pulse Graphs New issue Getting "VIDIOC_DQBUF error, Invalid Argument" on
V4l2_buf_type_video_capture
Linux kernel 3.0.36+ #12 Closed nickaein opened this Issue Jul 22, 2014 · 20 comments Projects None
V4l2 Example Application
yet Labels None yet Milestone No milestone Assignees TIS-Edgar 3 participants nickaein commented Jul 22, 2014 Hi, I get this error on kernel 3.0.36+: VIDIOC_DQBUF error 22, https://linuxtv.org/downloads/v4l-dvb-apis/vidioc-qbuf.html Invalid Argument when I run the following example code (provided by @TIS-Edgar at #11) for capturing images: https://gist.github.com/10f04501f49b6b3bf75e After debugging, apparently at the line 109 of v4ldevice.cpp (inside read_frame function) this error occurs. I checked capturing video of a webcam using guvcview and it didn't any this problem. TheImagingSource member TIS-Edgar commented Jul 22, 2014 Do you have a https://github.com/TheImagingSource/tiscamera/issues/12 few more information? Are you running the code as in the example or did you make any changes? Does that error always occur? Does dmesg print anything useful? I am having trouble reproducing this error, so any info is welcome. Do you maybe have the possibility to test this with a more recent kernel (say >= 3.8)? I doubt that would change anything but you never know. TIS-Edgar self-assigned this Jul 22, 2014 nickaein commented Jul 22, 2014 Yes, I've downloaded and compiled the code as is. It works without any error on Ubuntu 13.04 (with kernel 3.8) on a x86 machine, but due to some third-party drivers I've stuck on 3.0.36+ kernel on my ARM processor. The error always occur after running the example program. Here is the parts of dmesg I guess is important (I have uploaded the whole dmesg here: http://pastebin.com/pS7gB8cn): Registering the camera (during the boot): [ 4.019745] usb 2-1.4: new high speed USB device number 5 using usb20_host [ 4.120572] usb 2-1.4: New USB device found, idVendor=199e, idProduct=8308 [ 4.123743]
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back to Ubuntu with the 9.04 beta and later upgraded to the RC. I have a Generic BT878 chipset based TV card, and only today did I get around to seeing if it was configured properly. I had XawTV installed, my preferred TV application. When I run the program however, I don't get any video in the viewing window, only black. Running XawTV in the terminal gives me these errors: hazel@hazel-desktop:~$ xawtv This is xawtv-3.95.dfsg.1, running on Linux/i686 (2.6.28-11-generic) xinerama 0: 1680x1050+0+0 WARNING: No DGA direct video mode for this display. WARNING: couldn't find framebuffer base address, try manual configuration ("v4l-conf -a