vidioc-subdev-enum-frame-size.rst (3496B)
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 enumerate all frame sizes supported by 35a sub-device on the given pad for the given media bus format. Supported 36formats can be retrieved with the 37:ref:`VIDIOC_SUBDEV_ENUM_MBUS_CODE` 38ioctl. 39 40To enumerate frame sizes applications initialize the ``pad``, ``which`` 41, ``code`` and ``index`` fields of the struct 42:c:type:`v4l2_subdev_mbus_code_enum` and 43call the :ref:`VIDIOC_SUBDEV_ENUM_FRAME_SIZE` ioctl with a pointer to the 44structure. Drivers fill the minimum and maximum frame sizes or return an 45EINVAL error code if one of the input parameters is invalid. 46 47Sub-devices that only support discrete frame sizes (such as most 48sensors) will return one or more frame sizes with identical minimum and 49maximum values. 50 51Not all possible sizes in given [minimum, maximum] ranges need to be 52supported. For instance, a scaler that uses a fixed-point scaling ratio 53might not be able to produce every frame size between the minimum and 54maximum values. Applications must use the 55:ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>` ioctl to try the 56sub-device for an exact supported frame size. 57 58Available frame sizes may depend on the current 'try' formats at other 59pads of the sub-device, as well as on the current active links and the 60current values of V4L2 controls. See 61:ref:`VIDIOC_SUBDEV_G_FMT` for more 62information about try formats. 63 64.. c:type:: v4l2_subdev_frame_size_enum 65 66.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| 67 68.. flat-table:: struct v4l2_subdev_frame_size_enum 69 :header-rows: 0 70 :stub-columns: 0 71 :widths: 1 1 2 72 73 * - __u32 74 - ``index`` 75 - Number of the format in the enumeration, set by the application. 76 * - __u32 77 - ``pad`` 78 - Pad number as reported by the media controller API. 79 * - __u32 80 - ``code`` 81 - The media bus format code, as defined in 82 :ref:`v4l2-mbus-format`. 83 * - __u32 84 - ``min_width`` 85 - Minimum frame width, in pixels. 86 * - __u32 87 - ``max_width`` 88 - Maximum frame width, in pixels. 89 * - __u32 90 - ``min_height`` 91 - Minimum frame height, in pixels. 92 * - __u32 93 - ``max_height`` 94 - Maximum frame height, in pixels. 95 * - __u32 96 - ``which`` 97 - Frame sizes to be enumerated, from enum 98 :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. 99 * - __u32 100 - ``reserved``\ [8] 101 - Reserved for future extensions. Applications and drivers must set 102 the array to zero. 103 104Return Value 105============ 106 107On success 0 is returned, on error -1 and the ``errno`` variable is set 108appropriately. The generic error codes are described at the 109:ref:`Generic Error Codes <gen-errors>` chapter. 110 111EINVAL 112 The struct 113 :c:type:`v4l2_subdev_frame_size_enum` 114 ``pad`` references a non-existing pad, the ``code`` is invalid for 115 the given pad or the ``index`` field is out of bounds.