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The conversion script added some comments at the end. They point to the original DocBook files, with will be removed after the manual fixes. So, they'll be pointing to nowere. So, remove those comments. They'll be forever stored at the Kernel tree. So, if someone wants the references, it is just a matter of looking at the backlog. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
61 lines
1.5 KiB
ReStructuredText
61 lines
1.5 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
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.. _VIDIOC_PREPARE_BUF:
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************************
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ioctl VIDIOC_PREPARE_BUF
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************************
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*man VIDIOC_PREPARE_BUF(2)*
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Prepare a buffer for I/O
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Synopsis
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========
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.. cpp:function:: int ioctl( int fd, int request, struct v4l2_buffer *argp )
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <func-open>`.
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``request``
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VIDIOC_PREPARE_BUF
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``argp``
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Description
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===========
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Applications can optionally call the :ref:`VIDIOC_PREPARE_BUF` ioctl to
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pass ownership of the buffer to the driver before actually enqueuing it,
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using the :ref:`VIDIOC_QBUF` ioctl, and to prepare it for future I/O. Such
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preparations may include cache invalidation or cleaning. Performing them
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in advance saves time during the actual I/O. In case such cache
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operations are not required, the application can use one of
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``V4L2_BUF_FLAG_NO_CACHE_INVALIDATE`` and
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``V4L2_BUF_FLAG_NO_CACHE_CLEAN`` flags to skip the respective step.
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The :ref:`struct v4l2_buffer <v4l2-buffer>` structure is specified in
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:ref:`buffer`.
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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EBUSY
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File I/O is in progress.
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EINVAL
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The buffer ``type`` is not supported, or the ``index`` is out of
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bounds, or no buffers have been allocated yet, or the ``userptr`` or
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``length`` are invalid.
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