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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 | 26 |
1 files changed, 21 insertions, 5 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 4d56c0528ad7..b8698b85bd80 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst @@ -199,6 +199,10 @@ still cause this situation. - ``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 @@ -334,14 +338,26 @@ still cause this situation. - Which value of the control to get/set/try. * - :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 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 + 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. - 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. + 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. + + 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 |