From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../userspace-api/media/v4l/vidioc-prepare-buf.rst | 56 ++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/vidioc-prepare-buf.rst (limited to 'Documentation/userspace-api/media/v4l/vidioc-prepare-buf.rst') diff --git a/Documentation/userspace-api/media/v4l/vidioc-prepare-buf.rst b/Documentation/userspace-api/media/v4l/vidioc-prepare-buf.rst new file mode 100644 index 000000000..45bb1eab2 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-prepare-buf.rst @@ -0,0 +1,56 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _VIDIOC_PREPARE_BUF: + +************************ +ioctl VIDIOC_PREPARE_BUF +************************ + +Name +==== + +VIDIOC_PREPARE_BUF - Prepare a buffer for I/O + +Synopsis +======== + +.. c:macro:: VIDIOC_PREPARE_BUF + +``int ioctl(int fd, VIDIOC_PREPARE_BUF, struct v4l2_buffer *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :c:func:`open()`. + +``argp`` + Pointer to struct :c:type:`v4l2_buffer`. + +Description +=========== + +Applications can optionally call the :ref:`VIDIOC_PREPARE_BUF` ioctl to +pass ownership of the buffer to the driver before actually enqueuing it, +using the :ref:`VIDIOC_QBUF ` ioctl, and to prepare it for future I/O. Such +preparations may include cache invalidation or cleaning. Performing them +in advance saves time during the actual I/O. + +The struct :c:type:`v4l2_buffer` structure is specified in +:ref:`buffer`. + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes ` chapter. + +EBUSY + File I/O is in progress. + +EINVAL + The buffer ``type`` is not supported, or the ``index`` is out of + bounds, or no buffers have been allocated yet, or the ``userptr`` or + ``length`` are invalid. -- cgit v1.2.3