Commit f84dd900 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

doc-rst: linux_tv: Use references for read()/write() 



Use cross-references for read()/write() on a few places
where they weren't used.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 863bd721

Documentation/linux_tv/media/v4l/dev-capture.rst

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@@ -97,6 +97,6 @@ requests and always returns default parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_F 
Reading Images

==============



A video capture device may support the :ref:`read() function <rw>`

and/or streaming (:ref:`memory mapping <mmap>` or

A video capture device may support the ::ref:`read() function <func-read>`

and/or streaming (:ref:`memory mapping <func-mmap>` or

:ref:`user pointer <userp>`) I/O. See :ref:`io` for details.

Documentation/linux_tv/media/v4l/dev-raw-vbi.rst

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@@ -91,8 +91,8 @@ happen for instance when the video and VBI areas to capture would 
overlap, or when the driver supports multiple opens and another process

already requested VBI capturing or output. Anyway, applications must

expect other resource allocation points which may return ``EBUSY``, at the

:ref:`VIDIOC_STREAMON` ioctl and the first read(),

write() and select() call.

:ref:`VIDIOC_STREAMON` ioctl and the first :ref:`read() <func-read>`

, :ref:`write() <func-write>` and :ref:`select() <func-select>` calls.



VBI devices must implement both the :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` and

:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl, even if :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ignores all requests

Documentation/linux_tv/media/v4l/func-open.rst

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@@ -32,12 +32,12 @@ Arguments 
    technicality, input devices still support only reading and output

    devices only writing.



    When the ``O_NONBLOCK`` flag is given, the read() function and the

    :ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl will return the ``EAGAIN``

    error code when no data is available or no buffer is in the driver

    outgoing queue, otherwise these functions block until data becomes

    available. All V4L2 drivers exchanging data with applications must

    support the ``O_NONBLOCK`` flag.

    When the ``O_NONBLOCK`` flag is given, the :ref:`read() <func-read>`

    function and the :ref:`VIDIOC_DQBUF <VIDIOC_QBUF>` ioctl will

    return the ``EAGAIN`` error code when no data is available or no

    buffer is in the driver outgoing queue, otherwise these functions

    block until data becomes available. All V4L2 drivers exchanging data

    with applications must support the ``O_NONBLOCK`` flag.



    Other flags have no effect.

Documentation/linux_tv/media/v4l/open.rst

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@@ -73,7 +73,8 @@ support all functions. However, in practice this never worked: this 
'feature' was never used by applications and many drivers did not

support it and if they did it was certainly never tested. In addition,

switching a device node between different functions only works when

using the streaming I/O API, not with the read()/write() API.

using the streaming I/O API, not with the

:ref:`read() <func-read>`/\ :ref:`write() <func-write>` API.



Today each device node supports just one function.