Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) .. c:namespace:: V4L
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) .. _VIDIOC_PREPARE_BUF:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) ************************
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) ioctl VIDIOC_PREPARE_BUF
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) ************************
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) Name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) ====
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) VIDIOC_PREPARE_BUF - Prepare a buffer for I/O
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) Synopsis
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) ========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) .. c:macro:: VIDIOC_PREPARE_BUF
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) ``int ioctl(int fd, VIDIOC_PREPARE_BUF, struct v4l2_buffer *argp)``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) Arguments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) =========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) ``fd``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)     File descriptor returned by :c:func:`open()`.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) ``argp``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)     Pointer to struct :c:type:`v4l2_buffer`.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) ===========
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) Applications can optionally call the :ref:`VIDIOC_PREPARE_BUF` ioctl to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) pass ownership of the buffer to the driver before actually enqueuing it,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) using the :ref:`VIDIOC_QBUF <VIDIOC_QBUF>` ioctl, and to prepare it for future I/O. Such
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) preparations may include cache invalidation or cleaning. Performing them
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) in advance saves time during the actual I/O.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) The struct :c:type:`v4l2_buffer` structure is specified in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) :ref:`buffer`.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) Return Value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) ============
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) On success 0 is returned, on error -1 and the ``errno`` variable is set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) appropriately. The generic error codes are described at the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) :ref:`Generic Error Codes <gen-errors>` chapter.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) EBUSY
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)     File I/O is in progress.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) EINVAL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)     The buffer ``type`` is not supported, or the ``index`` is out of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)     bounds, or no buffers have been allocated yet, or the ``userptr`` or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)     ``length`` are invalid.