diff options
Diffstat (limited to 'Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 245 |
1 files changed, 191 insertions, 54 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst index add17c9204cb..b8698b85bd80 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst @@ -1,11 +1,5 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/userspace-api/media/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L .. _VIDIOC_G_EXT_CTRLS: @@ -18,32 +12,30 @@ Name VIDIOC_G_EXT_CTRLS - VIDIOC_S_EXT_CTRLS - VIDIOC_TRY_EXT_CTRLS - Get or set the value of several controls, try control values - Synopsis ======== -.. c:function:: int ioctl( int fd, VIDIOC_G_EXT_CTRLS, struct v4l2_ext_controls *argp ) - :name: VIDIOC_G_EXT_CTRLS +.. c:macro:: VIDIOC_G_EXT_CTRLS +``int ioctl(int fd, VIDIOC_G_EXT_CTRLS, struct v4l2_ext_controls *argp)`` -.. c:function:: int ioctl( int fd, VIDIOC_S_EXT_CTRLS, struct v4l2_ext_controls *argp ) - :name: VIDIOC_S_EXT_CTRLS +.. c:macro:: VIDIOC_S_EXT_CTRLS +``int ioctl(int fd, VIDIOC_S_EXT_CTRLS, struct v4l2_ext_controls *argp)`` -.. c:function:: int ioctl( int fd, VIDIOC_TRY_EXT_CTRLS, struct v4l2_ext_controls *argp ) - :name: VIDIOC_TRY_EXT_CTRLS +.. c:macro:: VIDIOC_TRY_EXT_CTRLS +``int ioctl(int fd, VIDIOC_TRY_EXT_CTRLS, struct v4l2_ext_controls *argp)`` Arguments ========= ``fd`` - File descriptor returned by :ref:`open() <func-open>`. + File descriptor returned by :c:func:`open()`. ``argp`` Pointer to struct :c:type:`v4l2_ext_controls`. - Description =========== @@ -61,7 +53,7 @@ by the ``controls`` fields. To get the current value of a set of controls applications initialize the ``id``, ``size`` and ``reserved2`` fields of each struct :c:type:`v4l2_ext_control` and call the -:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctl. String controls controls must also set the +:ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` ioctl. String controls must also set the ``string`` field. Controls of compound types (``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is set) must set the ``ptr`` field. @@ -126,12 +118,15 @@ correct. This prevents the situation where only some of the controls were set/get. Only low-level errors (e. g. a failed i2c command) can still cause this situation. - -.. tabularcolumns:: |p{1.2cm}|p{3.0cm}|p{1.5cm}|p{11.8cm}| +.. tabularcolumns:: |p{6.8cm}|p{4.0cm}|p{6.5cm}| .. c:type:: v4l2_ext_control -.. cssclass: longtable +.. raw:: latex + + \footnotesize + +.. cssclass:: longtable .. flat-table:: struct v4l2_ext_control :header-rows: 0 @@ -143,11 +138,12 @@ still cause this situation. - Identifies the control, set by the application. * - __u32 - ``size`` - - The total size in bytes of the payload of this control. This is - normally 0, but for pointer controls this should be set to the - size of the memory containing the payload, or that will receive - the payload. If :ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` finds that this value is - less than is required to store the payload result, then it is set + - The total size in bytes of the payload of this control. + * - :cspan:`2` The ``size`` field is normally 0, but for pointer + controls this should be set to the size of the memory that contains + the payload or that will receive the payload. + If :ref:`VIDIOC_G_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` finds that this value + is less than is required to store the payload result, then it is set to a value large enough to store the payload result and ``ENOSPC`` is returned. @@ -189,10 +185,128 @@ still cause this situation. - ``p_u32`` - A pointer to a matrix control of unsigned 32-bit values. Valid if this control is of type ``V4L2_CTRL_TYPE_U32``. - * - :c:type:`v4l2_area` * + * - __s32 * + - ``p_s32`` + - A pointer to a matrix control of signed 32-bit values. Valid if + this control is of type ``V4L2_CTRL_TYPE_INTEGER`` and + ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is set. + * - __s64 * + - ``p_s64`` + - A pointer to a matrix control of signed 64-bit values. Valid if + this control is of type ``V4L2_CTRL_TYPE_INTEGER64`` and + ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is set. + * - struct :c:type:`v4l2_area` * - ``p_area`` - A pointer to a struct :c:type:`v4l2_area`. Valid if this control is of type ``V4L2_CTRL_TYPE_AREA``. + * - struct :c:type:`v4l2_rect` * + - ``p_rect`` + - A pointer to a struct :c:type:`v4l2_rect`. Valid if this control is + of type ``V4L2_CTRL_TYPE_RECT``. + * - struct :c:type:`v4l2_ctrl_h264_sps` * + - ``p_h264_sps`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_sps`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_SPS``. + * - struct :c:type:`v4l2_ctrl_h264_pps` * + - ``p_h264_pps`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_pps`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_PPS``. + * - struct :c:type:`v4l2_ctrl_h264_scaling_matrix` * + - ``p_h264_scaling_matrix`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_scaling_matrix`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_SCALING_MATRIX``. + * - struct :c:type:`v4l2_ctrl_h264_pred_weights` * + - ``p_h264_pred_weights`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_pred_weights`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_PRED_WEIGHTS``. + * - struct :c:type:`v4l2_ctrl_h264_slice_params` * + - ``p_h264_slice_params`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_slice_params`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_SLICE_PARAMS``. + * - struct :c:type:`v4l2_ctrl_h264_decode_params` * + - ``p_h264_decode_params`` + - A pointer to a struct :c:type:`v4l2_ctrl_h264_decode_params`. Valid if this control is + of type ``V4L2_CTRL_TYPE_H264_DECODE_PARAMS``. + * - struct :c:type:`v4l2_ctrl_fwht_params` * + - ``p_fwht_params`` + - A pointer to a struct :c:type:`v4l2_ctrl_fwht_params`. Valid if this control is + of type ``V4L2_CTRL_TYPE_FWHT_PARAMS``. + * - struct :c:type:`v4l2_ctrl_vp8_frame` * + - ``p_vp8_frame`` + - A pointer to a struct :c:type:`v4l2_ctrl_vp8_frame`. Valid if this control is + of type ``V4L2_CTRL_TYPE_VP8_FRAME``. + * - struct :c:type:`v4l2_ctrl_mpeg2_sequence` * + - ``p_mpeg2_sequence`` + - A pointer to a struct :c:type:`v4l2_ctrl_mpeg2_sequence`. Valid if this control is + of type ``V4L2_CTRL_TYPE_MPEG2_SEQUENCE``. + * - struct :c:type:`v4l2_ctrl_mpeg2_picture` * + - ``p_mpeg2_picture`` + - A pointer to a struct :c:type:`v4l2_ctrl_mpeg2_picture`. Valid if this control is + of type ``V4L2_CTRL_TYPE_MPEG2_PICTURE``. + * - struct :c:type:`v4l2_ctrl_mpeg2_quantisation` * + - ``p_mpeg2_quantisation`` + - A pointer to a struct :c:type:`v4l2_ctrl_mpeg2_quantisation`. Valid if this control is + of type ``V4L2_CTRL_TYPE_MPEG2_QUANTISATION``. + * - struct :c:type:`v4l2_ctrl_vp9_compressed_hdr` * + - ``p_vp9_compressed_hdr_probs`` + - A pointer to a struct :c:type:`v4l2_ctrl_vp9_compressed_hdr`. Valid if this + control is of type ``V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR``. + * - struct :c:type:`v4l2_ctrl_vp9_frame` * + - ``p_vp9_frame`` + - A pointer to a struct :c:type:`v4l2_ctrl_vp9_frame`. Valid if this + control is of type ``V4L2_CTRL_TYPE_VP9_FRAME``. + * - struct :c:type:`v4l2_ctrl_hdr10_cll_info` * + - ``p_hdr10_cll`` + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_cll_info`. Valid if this control is + of type ``V4L2_CTRL_TYPE_HDR10_CLL_INFO``. + * - struct :c:type:`v4l2_ctrl_hdr10_mastering_display` * + - ``p_hdr10_mastering`` + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_mastering_display`. Valid if this control is + of type ``V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY``. + * - struct :c:type:`v4l2_ctrl_hevc_sps` * + - ``p_hevc_sps`` + - A pointer to a struct :c:type:`v4l2_ctrl_hevc_sps`. Valid if this + control is of type ``V4L2_CTRL_TYPE_HEVC_SPS``. + * - struct :c:type:`v4l2_ctrl_hevc_pps` * + - ``p_hevc_pps`` + - A pointer to a struct :c:type:`v4l2_ctrl_hevc_pps`. Valid if this + control is of type ``V4L2_CTRL_TYPE_HEVC_PPS``. + * - struct :c:type:`v4l2_ctrl_hevc_slice_params` * + - ``p_hevc_slice_params`` + - A pointer to a struct :c:type:`v4l2_ctrl_hevc_slice_params`. Valid if this + control is of type ``V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS``. + * - struct :c:type:`v4l2_ctrl_hevc_scaling_matrix` * + - ``p_hevc_scaling_matrix`` + - A pointer to a struct :c:type:`v4l2_ctrl_hevc_scaling_matrix`. Valid if this + control is of type ``V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX``. + * - struct :c:type:`v4l2_ctrl_hevc_decode_params` * + - ``p_hevc_decode_params`` + - A pointer to a struct :c:type:`v4l2_ctrl_hevc_decode_params`. Valid if this + control is of type ``V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS``. + * - struct :c:type:`v4l2_ctrl_av1_sequence` * + - ``p_av1_sequence`` + - A pointer to a struct :c:type:`v4l2_ctrl_av1_sequence`. Valid if this control is + of type ``V4L2_CTRL_TYPE_AV1_SEQUENCE``. + * - struct :c:type:`v4l2_ctrl_av1_tile_group_entry` * + - ``p_av1_tile_group_entry`` + - A pointer to a struct :c:type:`v4l2_ctrl_av1_tile_group_entry`. Valid if this control is + of type ``V4L2_CTRL_TYPE_AV1_TILE_GROUP_ENTRY``. + * - struct :c:type:`v4l2_ctrl_av1_frame` * + - ``p_av1_frame`` + - A pointer to a struct :c:type:`v4l2_ctrl_av1_frame`. Valid if this control is + of type ``V4L2_CTRL_TYPE_AV1_FRAME``. + * - struct :c:type:`v4l2_ctrl_av1_film_grain` * + - ``p_av1_film_grain`` + - A pointer to a struct :c:type:`v4l2_ctrl_av1_film_grain`. Valid if this control is + of type ``V4L2_CTRL_TYPE_AV1_FILM_GRAIN``. + * - struct :c:type:`v4l2_ctrl_hdr10_cll_info` * + - ``p_hdr10_cll_info`` + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_cll_info`. Valid if this control is + of type ``V4L2_CTRL_TYPE_HDR10_CLL_INFO``. + * - struct :c:type:`v4l2_ctrl_hdr10_mastering_display` * + - ``p_hdr10_mastering_display`` + - A pointer to a struct :c:type:`v4l2_ctrl_hdr10_mastering_display`. Valid if this control is + of type ``V4L2_CTRL_TYPE_HDR10_MASTERING_DISPLAY``. * - void * - ``ptr`` - A pointer to a compound type which can be an N-dimensional array @@ -202,8 +316,11 @@ still cause this situation. * - } - +.. raw:: latex -.. tabularcolumns:: |p{4.0cm}|p{2.2cm}|p{2.1cm}|p{8.2cm}| + \normalsize + +.. tabularcolumns:: |p{4.0cm}|p{2.5cm}|p{10.8cm}| .. c:type:: v4l2_ext_controls @@ -217,29 +334,30 @@ still cause this situation. * - union { - (anonymous) * - __u32 - - ``ctrl_class`` - - The control class to which all controls belong, see - :ref:`ctrl-class`. Drivers that use a kernel framework for - handling controls will also accept a value of 0 here, meaning that - the controls can belong to any control class. Whether drivers - support this can be tested by setting ``ctrl_class`` to 0 and - calling :ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` with a ``count`` of 0. If that - succeeds, then the driver supports this feature. - * - __u32 - ``which`` - Which value of the control to get/set/try. - ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of the - control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default - value of the control and ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that - these controls have to be retrieved from a request or tried/set for - a request. In the latter case the ``request_fd`` field contains the + * - :cspan:`2` ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of + the control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default + value of the control, ``V4L2_CTRL_WHICH_MIN_VAL`` will return the minimum + value of the control, and ``V4L2_CTRL_WHICH_MAX_VAL`` will return the maximum + value of the control. ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that + the control value has to be retrieved from a request or tried/set for + a request. In that case the ``request_fd`` field contains the file descriptor of the request that should be used. If the device does not support requests, then ``EACCES`` will be returned. - .. note:: + When using ``V4L2_CTRL_WHICH_DEF_VAL``, ``V4L2_CTRL_WHICH_MIN_VAL`` + or ``V4L2_CTRL_WHICH_MAX_VAL`` be aware that you can only get the + default/minimum/maximum value of the control, you cannot set or try it. - When using ``V4L2_CTRL_WHICH_DEF_VAL`` be aware that you can only - get the default value of the control, you cannot set or try it. + Whether a control supports querying the minimum and maximum values using + ``V4L2_CTRL_WHICH_MIN_VAL`` and ``V4L2_CTRL_WHICH_MAX_VAL`` is indicated + by the ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. Most non-compound + control types support this. For controls with compound types, the + definition of minimum/maximum values are provided by + the control documentation. If a compound control does not document the + meaning of minimum/maximum value, then querying the minimum or maximum + value will result in the error code -EINVAL. For backwards compatibility you can also use a control class here (see :ref:`ctrl-class`). In that case all controls have to @@ -247,9 +365,12 @@ still cause this situation. just use ``V4L2_CTRL_WHICH_CUR_VAL``. There are some very old drivers that do not yet support ``V4L2_CTRL_WHICH_CUR_VAL`` and that require a control class here. You can test for such drivers - by setting ctrl_class to ``V4L2_CTRL_WHICH_CUR_VAL`` and calling - VIDIOC_TRY_EXT_CTRLS with a count of 0. If that fails, then the - driver does not support ``V4L2_CTRL_WHICH_CUR_VAL``. + by setting ``which`` to ``V4L2_CTRL_WHICH_CUR_VAL`` and calling + :ref:`VIDIOC_TRY_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` with a count of 0. + If that fails, then the driver does not support ``V4L2_CTRL_WHICH_CUR_VAL``. + * - __u32 + - ``ctrl_class`` + - Deprecated name kept for backwards compatibility. Use ``which`` instead. * - } - * - __u32 @@ -257,7 +378,8 @@ still cause this situation. - The number of controls in the controls array. May also be zero. * - __u32 - ``error_idx`` - - Set by the driver in case of an error. If the error is associated + - Index of the failing control. Set by the driver in case of an error. + * - :cspan:`2` If the error is associated with a particular control, then ``error_idx`` is set to the index of that control. If the error is not related to a specific control, or the validation step failed (see below), then @@ -316,8 +438,9 @@ still cause this situation. Ignored if ``count`` equals zero. +.. tabularcolumns:: |p{7.3cm}|p{2.0cm}|p{8.0cm}| -.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| +.. cssclass:: longtable .. _ctrl-class: @@ -333,10 +456,10 @@ still cause this situation. :ref:`VIDIOC_S_CTRL <VIDIOC_G_CTRL>` and :ref:`VIDIOC_G_CTRL <VIDIOC_G_CTRL>` ioctl belong to this class. - * - ``V4L2_CTRL_CLASS_MPEG`` + * - ``V4L2_CTRL_CLASS_CODEC`` - 0x990000 - - The class containing MPEG compression controls. These controls are - described in :ref:`mpeg-controls`. + - The class containing stateful codec controls. These controls are + described in :ref:`codec-controls`. * - ``V4L2_CTRL_CLASS_CAMERA`` - 0x9a0000 - The class containing camera controls. These controls are described @@ -369,7 +492,18 @@ still cause this situation. - 0xa20000 - The class containing RF tuner controls. These controls are described in :ref:`rf-tuner-controls`. - + * - ``V4L2_CTRL_CLASS_DETECT`` + - 0xa30000 + - The class containing motion or object detection controls. These controls + are described in :ref:`detect-controls`. + * - ``V4L2_CTRL_CLASS_CODEC_STATELESS`` + - 0xa40000 + - The class containing stateless codec controls. These controls are + described in :ref:`codec-stateless-controls`. + * - ``V4L2_CTRL_CLASS_COLORIMETRY`` + - 0xa50000 + - The class containing colorimetry controls. These controls are + described in :ref:`colorimetry-controls`. Return Value ============ @@ -414,3 +548,6 @@ EACCES Or the ``which`` field was set to ``V4L2_CTRL_WHICH_REQUEST_VAL`` but the device does not support requests. + + Or if there is an attempt to set an inactive control and the driver is + not capable of caching the new value until the control is active again. |