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Add support to manage configurations (format, crop, compose) per stream, instead of per pad. This is accomplished with data structures that hold an array of all subdev's stream configurations. The number of streams can vary at runtime based on routing. Every time the routing is changed, the stream configurations need to be re-initialized. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
119 lines
3.5 KiB
ReStructuredText
119 lines
3.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
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.. c:namespace:: V4L
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.. _VIDIOC_SUBDEV_ENUM_FRAME_SIZE:
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***********************************
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ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE
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***********************************
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Name
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====
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VIDIOC_SUBDEV_ENUM_FRAME_SIZE - Enumerate media bus frame sizes
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Synopsis
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========
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.. c:macro:: VIDIOC_SUBDEV_ENUM_FRAME_SIZE
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``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, struct v4l2_subdev_frame_size_enum * argp)``
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Arguments
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=========
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``fd``
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File descriptor returned by :c:func:`open()`.
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``argp``
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Pointer to struct :c:type:`v4l2_subdev_frame_size_enum`.
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Description
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===========
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This ioctl allows applications to enumerate all frame sizes supported by
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a sub-device on the given pad for the given media bus format. Supported
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formats can be retrieved with the
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:ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE`
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ioctl.
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To enumerate frame sizes applications initialize the ``pad``, ``which``
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, ``code`` and ``index`` fields of the struct
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:c:type:`v4l2_subdev_mbus_code_enum` and
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call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_SIZE` ioctl with a pointer to the
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structure. Drivers fill the minimum and maximum frame sizes or return an
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EINVAL error code if one of the input parameters is invalid.
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Sub-devices that only support discrete frame sizes (such as most
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sensors) will return one or more frame sizes with identical minimum and
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maximum values.
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Not all possible sizes in given [minimum, maximum] ranges need to be
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supported. For instance, a scaler that uses a fixed-point scaling ratio
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might not be able to produce every frame size between the minimum and
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maximum values. Applications must use the
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:ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctl to try the
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sub-device for an exact supported frame size.
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Available frame sizes may depend on the current 'try' formats at other
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pads of the sub-device, as well as on the current active links and the
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current values of V4L2 controls. See
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:ref:`VIDIOC_SUBDEV_G_FMT` for more
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information about try formats.
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.. c:type:: v4l2_subdev_frame_size_enum
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.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}|
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.. flat-table:: struct v4l2_subdev_frame_size_enum
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 1 2
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* - __u32
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- ``index``
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- Number of the format in the enumeration, set by the application.
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* - __u32
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- ``pad``
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- Pad number as reported by the media controller API.
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* - __u32
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- ``code``
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- The media bus format code, as defined in
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:ref:`v4l2-mbus-format`.
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* - __u32
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- ``min_width``
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- Minimum frame width, in pixels.
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* - __u32
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- ``max_width``
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- Maximum frame width, in pixels.
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* - __u32
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- ``min_height``
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- Minimum frame height, in pixels.
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* - __u32
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- ``max_height``
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- Maximum frame height, in pixels.
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* - __u32
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- ``which``
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- Frame sizes to be enumerated, from enum
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:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
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* - __u32
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- ``stream``
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- Stream identifier.
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* - __u32
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- ``reserved``\ [7]
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- Reserved for future extensions. Applications and drivers must set
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the array to zero.
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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
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:c:type:`v4l2_subdev_frame_size_enum`
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``pad`` references a non-existing pad, the ``code`` is invalid for
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the given pad or the ``index`` field is out of bounds.
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