mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
8968da9b86
This patch touches on places where it shouldn't: image
files and code examples. Also, it doesn't fix all array
occurrences.
So, let's revert it.
This reverts commit ffbab694ed.
145 lines
3.3 KiB
ReStructuredText
145 lines
3.3 KiB
ReStructuredText
.. -*- coding: utf-8; mode: rst -*-
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.. _VIDIOC_SUBDEV_G_SELECTION:
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**********************************************************
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ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION
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**********************************************************
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Name
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====
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VIDIOC_SUBDEV_G_SELECTION - VIDIOC_SUBDEV_S_SELECTION - Get or set selection rectangles on a subdev pad
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Synopsis
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========
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.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_selection *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_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION
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``argp``
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Description
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===========
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The selections are used to configure various image processing
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functionality performed by the subdevs which affect the image size. This
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currently includes cropping, scaling and composition.
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The selection API replaces
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:ref:`the old subdev crop API <VIDIOC_SUBDEV_G_CROP>`. All the
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function of the crop API, and more, are supported by the selections API.
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See :ref:`subdev` for more information on how each selection target
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affects the image processing pipeline inside the subdevice.
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Types of selection targets
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--------------------------
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There are two types of selection targets: actual and bounds. The actual
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targets are the targets which configure the hardware. The BOUNDS target
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will return a rectangle that contain all possible actual rectangles.
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Discovering supported features
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------------------------------
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To discover which targets are supported, the user can perform
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``VIDIOC_SUBDEV_G_SELECTION`` on them. Any unsupported target will
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return ``EINVAL``.
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Selection targets and flags are documented in
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:ref:`v4l2-selections-common`.
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.. _v4l2-subdev-selection:
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.. flat-table:: struct v4l2_subdev_selection
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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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- .. row 1
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- __u32
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- ``which``
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- Active or try selection, from enum
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:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
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- .. row 2
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- __u32
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- ``pad``
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- Pad number as reported by the media framework.
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- .. row 3
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- __u32
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- ``target``
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- Target selection rectangle. See :ref:`v4l2-selections-common`.
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- .. row 4
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- __u32
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- ``flags``
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- Flags. See :ref:`v4l2-selection-flags`.
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- .. row 5
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- struct :ref:`v4l2_rect <v4l2-rect>`
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- ``r``
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- Selection rectangle, in pixels.
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- .. row 6
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- __u32
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- ``reserved``\ [8]
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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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EBUSY
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The selection rectangle can't be changed because the pad is
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currently busy. This can be caused, for instance, by an active video
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stream on the pad. The ioctl must not be retried without performing
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another action to fix the problem first. Only returned by
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``VIDIOC_SUBDEV_S_SELECTION``
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EINVAL
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The struct :ref:`v4l2_subdev_selection <v4l2-subdev-selection>`
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``pad`` references a non-existing pad, the ``which`` field
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references a non-existing format, or the selection target is not
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supported on the given subdev pad.
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