1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _VIDIOC_SUBDEV_ENUM_FRAME_SIZE: 5 6*********************************** 7ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE 8*********************************** 9 10Name 11==== 12 13VIDIOC_SUBDEV_ENUM_FRAME_SIZE - Enumerate media bus frame sizes 14 15Synopsis 16======== 17 18.. c:macro:: VIDIOC_SUBDEV_ENUM_FRAME_SIZE 19 20``int ioctl(int fd, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, struct v4l2_subdev_frame_size_enum * argp)`` 21 22Arguments 23========= 24 25``fd`` 26 File descriptor returned by :c:func:`open()`. 27 28``argp`` 29 Pointer to struct :c:type:`v4l2_subdev_frame_size_enum`. 30 31Description 32=========== 33 34This ioctl allows applications to access the enumeration of frame sizes 35supported by a sub-device on the specified pad 36for the specified media bus format. 37Supported formats can be retrieved with the 38:ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` 39ioctl. 40 41The enumerations are defined by the driver, and indexed using the ``index`` field 42of the struct :c:type:`v4l2_subdev_frame_size_enum`. 43Each pair of ``pad`` and ``code`` correspond to a separate enumeration. 44Each enumeration starts with the ``index`` of 0, and 45the lowest invalid index marks the end of the enumeration. 46 47Therefore, to enumerate frame sizes allowed on the specified pad 48and using the specified mbus format, initialize the 49``pad``, ``which``, and ``code`` fields to desired values, 50and set ``index`` to 0. 51Then call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_SIZE` ioctl with a pointer to the 52structure. 53 54A successful call will return with minimum and maximum frame sizes filled in. 55Repeat with increasing ``index`` until ``EINVAL`` is received. 56``EINVAL`` means that either no more entries are available in the enumeration, 57or that an input parameter was invalid. 58 59Sub-devices that only support discrete frame sizes (such as most 60sensors) will return one or more frame sizes with identical minimum and 61maximum values. 62 63Not all possible sizes in given [minimum, maximum] ranges need to be 64supported. For instance, a scaler that uses a fixed-point scaling ratio 65might not be able to produce every frame size between the minimum and 66maximum values. Applications must use the 67:ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctl to try the 68sub-device for an exact supported frame size. 69 70Available frame sizes may depend on the current 'try' formats at other 71pads of the sub-device, as well as on the current active links and the 72current values of V4L2 controls. See 73:ref:`VIDIOC_SUBDEV_G_FMT` for more 74information about try formats. 75 76.. c:type:: v4l2_subdev_frame_size_enum 77 78.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| 79 80.. flat-table:: struct v4l2_subdev_frame_size_enum 81 :header-rows: 0 82 :stub-columns: 0 83 :widths: 1 1 2 84 85 * - __u32 86 - ``index`` 87 - Index of the frame size in the enumeration belonging to the given pad 88 and format. Filled in by the application. 89 * - __u32 90 - ``pad`` 91 - Pad number as reported by the media controller API. 92 Filled in by the application. 93 * - __u32 94 - ``code`` 95 - The media bus format code, as defined in 96 :ref:`v4l2-mbus-format`. Filled in by the application. 97 * - __u32 98 - ``min_width`` 99 - Minimum frame width, in pixels. Filled in by the driver. 100 * - __u32 101 - ``max_width`` 102 - Maximum frame width, in pixels. Filled in by the driver. 103 * - __u32 104 - ``min_height`` 105 - Minimum frame height, in pixels. Filled in by the driver. 106 * - __u32 107 - ``max_height`` 108 - Maximum frame height, in pixels. Filled in by the driver. 109 * - __u32 110 - ``which`` 111 - Frame sizes to be enumerated, from enum 112 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. 113 * - __u32 114 - ``stream`` 115 - Stream identifier. 116 * - __u32 117 - ``reserved``\ [7] 118 - Reserved for future extensions. Applications and drivers must set 119 the array to zero. 120 121Return Value 122============ 123 124On success 0 is returned, on error -1 and the ``errno`` variable is set 125appropriately. The generic error codes are described at the 126:ref:`Generic Error Codes <gen-errors>` chapter. 127 128EINVAL 129 The struct :c:type:`v4l2_subdev_frame_size_enum` ``pad`` references a 130 non-existing pad, the ``which`` field has an unsupported value, the ``code`` 131 is invalid for the given pad, or the ``index`` field is out of bounds. 132