From d0b2f91bede3bd5e3d24dd6803e56eee959c1797 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Thu, 20 Oct 2016 00:10:27 -0300 Subject: Linux-libre 4.8.2-gnu --- .../media/uapi/v4l/vidioc-subdev-g-selection.rst | 144 +++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst (limited to 'Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst') diff --git a/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst b/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst new file mode 100644 index 000000000..50838a4a4 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst @@ -0,0 +1,144 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_SUBDEV_G_SELECTION: + +********************************************************** +ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION +********************************************************** + +Name +==== + +VIDIOC_SUBDEV_G_SELECTION - VIDIOC_SUBDEV_S_SELECTION - Get or set selection rectangles on a subdev pad + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct v4l2_subdev_selection *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() `. + +``request`` + VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION + +``argp`` + + +Description +=========== + +The selections are used to configure various image processing +functionality performed by the subdevs which affect the image size. This +currently includes cropping, scaling and composition. + +The selection API replaces +:ref:`the old subdev crop API `. All the +function of the crop API, and more, are supported by the selections API. + +See :ref:`subdev` for more information on how each selection target +affects the image processing pipeline inside the subdevice. + + +Types of selection targets +-------------------------- + +There are two types of selection targets: actual and bounds. The actual +targets are the targets which configure the hardware. The BOUNDS target +will return a rectangle that contain all possible actual rectangles. + + +Discovering supported features +------------------------------ + +To discover which targets are supported, the user can perform +``VIDIOC_SUBDEV_G_SELECTION`` on them. Any unsupported target will +return ``EINVAL``. + +Selection targets and flags are documented in +:ref:`v4l2-selections-common`. + + +.. _v4l2-subdev-selection: + +.. flat-table:: struct v4l2_subdev_selection + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + + - .. row 1 + + - __u32 + + - ``which`` + + - Active or try selection, from enum + :ref:`v4l2_subdev_format_whence `. + + - .. row 2 + + - __u32 + + - ``pad`` + + - Pad number as reported by the media framework. + + - .. row 3 + + - __u32 + + - ``target`` + + - Target selection rectangle. See :ref:`v4l2-selections-common`. + + - .. row 4 + + - __u32 + + - ``flags`` + + - Flags. See :ref:`v4l2-selection-flags`. + + - .. row 5 + + - struct :ref:`v4l2_rect ` + + - ``r`` + + - Selection rectangle, in pixels. + + - .. row 6 + + - __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 ` chapter. + +EBUSY + The selection rectangle can't be changed because the pad is + currently busy. This can be caused, for instance, by an active video + stream on the pad. The ioctl must not be retried without performing + another action to fix the problem first. Only returned by + ``VIDIOC_SUBDEV_S_SELECTION`` + +EINVAL + The struct :ref:`v4l2_subdev_selection ` + ``pad`` references a non-existing pad, the ``which`` field + references a non-existing format, or the selection target is not + supported on the given subdev pad. -- cgit v1.2.3-54-g00ecf