mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-29 07:34:06 +08:00
c2b66cafdf
Shorten the tables by removing row numbers in comments, allowing for
later insertion of rows with minimal diffs.
All changes have been generated by the following script.
import io
import re
import sys
def process_table(fname, data):
if fname.endswith('hist-v4l2.rst'):
data = re.sub(u'\n{1,2}\t( ?) -( ?) ?', u'\n\t\\1 -\\2', data, flags = re.MULTILINE)
data = re.sub(u'\n(\t| )- \.\. row [0-9]+\n\t ?-( ?) ?', u'\\1* -\\2', data, flags = re.MULTILINE)
else:
data = re.sub(u'\n{1,2} -( ?) ?', u'\n -\\1', data, flags = re.MULTILINE)
data = re.sub(u'(\n?)(\n\n - \.\. row 1\n)', u'\n\\2', data, flags = re.MULTILINE)
data = re.sub(u'\n - \.\. row [0-9]+\n -( ?) ?', u' * -\\1', data, flags = re.MULTILINE)
data = re.sub(u'\n - \.\. row [0-9]+\n \.\. (_[A-Z0-9_`-]*:)', u'\n - .. \\1', data, flags = re.MULTILINE)
data = re.sub(u'\n - \.\. (_[A-Z0-9_`-]*:)\n -', u' * .. \\1\n\n -', data, flags = re.MULTILINE)
data = re.sub(u'^ - ', u' -', data, flags = re.MULTILINE)
data = re.sub(u'^(\t{1,2}) ', u'\\1', data, flags = re.MULTILINE)
return data
def process_file(fname, data):
buf = io.StringIO(data)
output = ''
in_table = False
table_separator = 0
for line in buf.readlines():
if line.find('.. flat-table::') != -1:
in_table = True
table = ''
elif in_table and not re.match('^[\t\n]|( )', line):
in_table = False
output += process_table(fname, table)
if in_table:
table += line
else:
output += line
if in_table:
in_table = False
output += process_table(fname, table)
return output
fname = sys.argv[1]
data = file(fname, 'rb').read().decode('utf-8')
data = process_file(fname, data)
file(fname, 'wb').write(data.encode('utf-8'))
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
150 lines
5.4 KiB
ReStructuredText
150 lines
5.4 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
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.. _VIDIOC_G_FMT:
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************************************************
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ioctl VIDIOC_G_FMT, VIDIOC_S_FMT, VIDIOC_TRY_FMT
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************************************************
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Name
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====
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VIDIOC_G_FMT - VIDIOC_S_FMT - VIDIOC_TRY_FMT - Get or set the data format, try a format
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Synopsis
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========
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.. c:function:: int ioctl( int fd, VIDIOC_G_FMT, struct v4l2_format *argp )
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:name: VIDIOC_G_FMT
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.. c:function:: int ioctl( int fd, VIDIOC_S_FMT, struct v4l2_format *argp )
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:name: VIDIOC_S_FMT
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.. c:function:: int ioctl( int fd, VIDIOC_TRY_FMT, struct v4l2_format *argp )
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:name: VIDIOC_TRY_FMT
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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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``argp``
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Description
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===========
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These ioctls are used to negotiate the format of data (typically image
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format) exchanged between driver and application.
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To query the current parameters applications set the ``type`` field of a
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struct :c:type:`v4l2_format` to the respective buffer (stream)
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type. For example video capture devices use
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``V4L2_BUF_TYPE_VIDEO_CAPTURE`` or
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``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``. When the application calls the
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:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl with a pointer to this structure the driver fills
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the respective member of the ``fmt`` union. In case of video capture
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devices that is either the struct
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:c:type:`v4l2_pix_format` ``pix`` or the struct
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:c:type:`v4l2_pix_format_mplane` ``pix_mp``
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member. When the requested buffer type is not supported drivers return
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an ``EINVAL`` error code.
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To change the current format parameters applications initialize the
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``type`` field and all fields of the respective ``fmt`` union member.
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For details see the documentation of the various devices types in
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:ref:`devices`. Good practice is to query the current parameters
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first, and to modify only those parameters not suitable for the
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application. When the application calls the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
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a pointer to a struct :c:type:`v4l2_format` structure the driver
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checks and adjusts the parameters against hardware abilities. Drivers
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should not return an error code unless the ``type`` field is invalid,
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this is a mechanism to fathom device capabilities and to approach
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parameters acceptable for both the application and driver. On success
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the driver may program the hardware, allocate resources and generally
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prepare for data exchange. Finally the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl returns
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the current format parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does. Very simple,
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inflexible devices may even ignore all input and always return the
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default parameters. However all V4L2 devices exchanging data with the
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application must implement the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`
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ioctl. When the requested buffer type is not supported drivers return an
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EINVAL error code on a :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` attempt. When I/O is already in
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progress or the resource is not available for other reasons drivers
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return the ``EBUSY`` error code.
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The :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctl is equivalent to :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` with one
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exception: it does not change driver state. It can also be called at any
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time, never returning ``EBUSY``. This function is provided to negotiate
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parameters, to learn about hardware limitations, without disabling I/O
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or possibly time consuming hardware preparations. Although strongly
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recommended drivers are not required to implement this ioctl.
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The format as returned by :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` must be identical to what
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:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` returns for the same input or output.
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.. c:type:: v4l2_format
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.. tabularcolumns:: |p{1.2cm}|p{4.3cm}|p{3.0cm}|p{9.0cm}|
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.. flat-table:: struct v4l2_format
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:header-rows: 0
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:stub-columns: 0
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* - __u32
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- ``type``
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-
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- Type of the data stream, see :c:type:`v4l2_buf_type`.
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* - union
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- ``fmt``
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* -
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- struct :c:type:`v4l2_pix_format`
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- ``pix``
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- Definition of an image format, see :ref:`pixfmt`, used by video
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capture and output devices.
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* -
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- struct :c:type:`v4l2_pix_format_mplane`
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- ``pix_mp``
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- Definition of an image format, see :ref:`pixfmt`, used by video
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capture and output devices that support the
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:ref:`multi-planar version of the API <planar-apis>`.
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* -
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- struct :c:type:`v4l2_window`
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- ``win``
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- Definition of an overlaid image, see :ref:`overlay`, used by
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video overlay devices.
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* -
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- struct :c:type:`v4l2_vbi_format`
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- ``vbi``
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- Raw VBI capture or output parameters. This is discussed in more
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detail in :ref:`raw-vbi`. Used by raw VBI capture and output
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devices.
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* -
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- struct :c:type:`v4l2_sliced_vbi_format`
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- ``sliced``
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- Sliced VBI capture or output parameters. See :ref:`sliced` for
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details. Used by sliced VBI capture and output devices.
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* -
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- struct :c:type:`v4l2_sdr_format`
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- ``sdr``
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- Definition of a data format, see :ref:`pixfmt`, used by SDR
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capture and output devices.
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* -
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- __u8
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- ``raw_data``\ [200]
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- Place holder for future extensions.
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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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EINVAL
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The struct :c:type:`v4l2_format` ``type`` field is
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invalid or the requested buffer type not supported.
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