From 670027c507e99521d416994a18a498def9ef2ea3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Sat, 22 Oct 2016 19:31:08 -0300 Subject: Linux-libre 4.8.3-gnu --- Documentation/DocBook/media/v4l/vidioc-reqbufs.xml | 137 --------------------- 1 file changed, 137 deletions(-) delete mode 100644 Documentation/DocBook/media/v4l/vidioc-reqbufs.xml (limited to 'Documentation/DocBook/media/v4l/vidioc-reqbufs.xml') diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml deleted file mode 100644 index 0f193fda0..000000000 --- a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml +++ /dev/null @@ -1,137 +0,0 @@ - - - ioctl VIDIOC_REQBUFS - &manvol; - - - - VIDIOC_REQBUFS - Initiate Memory Mapping or User Pointer I/O - - - - - - int ioctl - int fd - int request - struct v4l2_requestbuffers *argp - - - - - - Arguments - - - - fd - - &fd; - - - - request - - VIDIOC_REQBUFS - - - - argp - - - - - - - - - Description - -This ioctl is used to initiate memory mapped, -user pointer or DMABUF based I/O. Memory mapped buffers are located in -device memory and must be allocated with this ioctl before they can be mapped -into the application's address space. User buffers are allocated by -applications themselves, and this ioctl is merely used to switch the driver -into user pointer I/O mode and to setup some internal structures. -Similarly, DMABUF buffers are allocated by applications through a device -driver, and this ioctl only configures the driver into DMABUF I/O mode without -performing any direct allocation. - - To allocate device buffers applications initialize all fields of the -v4l2_requestbuffers structure. They set the -type field to the respective stream or buffer type, -the count field to the desired number of buffers, -memory must be set to the requested I/O method and -the reserved array must be zeroed. When the ioctl is -called with a pointer to this structure the driver will attempt to allocate the -requested number of buffers and it stores the actual number allocated in the -count field. It can be smaller than the number -requested, even zero, when the driver runs out of free memory. A larger number -is also possible when the driver requires more buffers to function correctly. -For example video output requires at least two buffers, one displayed and one -filled by the application. - When the I/O method is not supported the ioctl -returns an &EINVAL;. - - Applications can call VIDIOC_REQBUFS -again to change the number of buffers, however this cannot succeed -when any buffers are still mapped. A count -value of zero frees all buffers, after aborting or finishing any DMA -in progress, an implicit &VIDIOC-STREAMOFF;. - - - struct <structname>v4l2_requestbuffers</structname> - - &cs-str; - - - __u32 - count - The number of buffers requested or granted. - - - __u32 - type - Type of the stream or buffers, this is the same -as the &v4l2-format; type field. See for valid values. - - - __u32 - memory - Applications set this field to -V4L2_MEMORY_MMAP, -V4L2_MEMORY_DMABUF or -V4L2_MEMORY_USERPTR. See . - - - __u32 - reserved[2] - A place holder for future extensions. Drivers and applications -must set the array to zero. - - - -
- - - - &return-value; - - - - EINVAL - - The buffer type (type field) or the -requested I/O method (memory) is not -supported. - - - - - -- cgit v1.2.3