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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 14:58:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 14:58:31 -0700
commitff9a082fda424257976f08fce942609f358015e0 (patch)
tree478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/uapi/v4l/vidioc-subdev-enum-frame-size.rst
parent6a492b0f23d28e1f946cdf08e54617484400dafb (diff)
parent85538b1ad145c67198cb55d02de14ba269cc323d (diff)
Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media documentation updates from Mauro Carvalho Chehab: "This patch series does the conversion of all media documentation stuff to Restrutured Text markup format and add them to the Documentation/index.rst file. The media documentation was grouped into 4 books: - media uAPI - media kAPI - V4L driver-specific documentation - DVB driver-specific documentation It also contains several documentation improvements and one fixup patch for a core issue with cropcap. PS. After this patch series, the media DocBook is deprecated and should be removed. I'll add such patch on a future pull request" * tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits) [media] cx23885-cardlist.rst: add a new card [media] doc-rst: add some needed escape codes [media] doc-rst: kapi: use :c:func: instead of :cpp:func doc-rst: kernel-doc: fix a change introduced by mistake [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops [media] dvb_ringbuffer.h: some documentation improvements [media] v4l2-ctrls.h: fully document the header file [media] doc-rst: Fix some typedef ugly warnings [media] doc-rst: reorganize the kAPI v4l2 chapters [media] rename v4l2-framework.rst to v4l2-intro.rst [media] move V4L2 clocks to a separate .rst file [media] v4l2-fh.rst: add cross references and markups [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst [media] v4l2-fh.h: add documentation for it [media] v4l2-event.rst: add cross-references and markups [media] v4l2-event.h: document all functions [media] v4l2-event.rst: add text from v4l2-framework.rst [media] v4l2-framework.rst: remove videobuf quick chapter [media] v4l2-dev: add cross-references and improve markup [media] doc-rst: move v4l2-dev doc to a separate file ...
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_SUBDEV_ENUM_FRAME_SIZE:
+
+***********************************
+ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE
+***********************************
+
+Name
+====
+
+VIDIOC_SUBDEV_ENUM_FRAME_SIZE - Enumerate media bus frame sizes
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_frame_size_enum * argp )
+
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+ VIDIOC_SUBDEV_ENUM_FRAME_SIZE
+
+``argp``
+
+
+Description
+===========
+
+This ioctl allows applications to enumerate all frame sizes supported by
+a sub-device on the given pad for the given media bus format. Supported
+formats can be retrieved with the
+:ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE`
+ioctl.
+
+To enumerate frame sizes applications initialize the ``pad``, ``which``
+, ``code`` and ``index`` fields of the struct
+:ref:`v4l2_subdev_mbus_code_enum <v4l2-subdev-mbus-code-enum>` and
+call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_SIZE` ioctl with a pointer to the
+structure. Drivers fill the minimum and maximum frame sizes or return an
+EINVAL error code if one of the input parameters is invalid.
+
+Sub-devices that only support discrete frame sizes (such as most
+sensors) will return one or more frame sizes with identical minimum and
+maximum values.
+
+Not all possible sizes in given [minimum, maximum] ranges need to be
+supported. For instance, a scaler that uses a fixed-point scaling ratio
+might not be able to produce every frame size between the minimum and
+maximum values. Applications must use the
+:ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctl to try the
+sub-device for an exact supported frame size.
+
+Available frame sizes may depend on the current 'try' formats at other
+pads of the sub-device, as well as on the current active links and the
+current values of V4L2 controls. See
+:ref:`VIDIOC_SUBDEV_G_FMT` for more
+information about try formats.
+
+
+.. _v4l2-subdev-frame-size-enum:
+
+.. flat-table:: struct v4l2_subdev_frame_size_enum
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 1 1 2
+
+
+ - .. row 1
+
+ - __u32
+
+ - ``index``
+
+ - Number of the format in the enumeration, set by the application.
+
+ - .. row 2
+
+ - __u32
+
+ - ``pad``
+
+ - Pad number as reported by the media controller API.
+
+ - .. row 3
+
+ - __u32
+
+ - ``code``
+
+ - The media bus format code, as defined in
+ :ref:`v4l2-mbus-format`.
+
+ - .. row 4
+
+ - __u32
+
+ - ``min_width``
+
+ - Minimum frame width, in pixels.
+
+ - .. row 5
+
+ - __u32
+
+ - ``max_width``
+
+ - Maximum frame width, in pixels.
+
+ - .. row 6
+
+ - __u32
+
+ - ``min_height``
+
+ - Minimum frame height, in pixels.
+
+ - .. row 7
+
+ - __u32
+
+ - ``max_height``
+
+ - Maximum frame height, in pixels.
+
+ - .. row 8
+
+ - __u32
+
+ - ``which``
+
+ - Frame sizes to be enumerated, from enum
+ :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
+
+ - .. row 9
+
+ - __u32
+
+ - ``reserved``\ [8]
+
+ - Reserved for future extensions. Applications and drivers must set
+ the array to zero.
+
+
+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 <gen-errors>` chapter.
+
+EINVAL
+ The struct
+ :ref:`v4l2_subdev_frame_size_enum <v4l2-subdev-frame-size-enum>`
+ ``pad`` references a non-existing pad, the ``code`` is invalid for
+ the given pad or the ``index`` field is out of bounds.