diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 51 |
1 files changed, 43 insertions, 8 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml index e9f6735c0823..c5bdbfcc42b3 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -72,23 +72,30 @@ initialize the <structfield>id</structfield>, <structfield>size</structfield> and <structfield>reserved2</structfield> fields of each &v4l2-ext-control; and call the <constant>VIDIOC_G_EXT_CTRLS</constant> ioctl. String controls controls -must also set the <structfield>string</structfield> field.</para> +must also set the <structfield>string</structfield> field. Controls +of compound types (<constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is set) +must set the <structfield>ptr</structfield> field.</para> <para>If the <structfield>size</structfield> is too small to receive the control result (only relevant for pointer-type controls like strings), then the driver will set <structfield>size</structfield> to a valid value and return an &ENOSPC;. You should re-allocate the -string memory to this new size and try again. It is possible that the -same issue occurs again if the string has grown in the meantime. It is +memory to this new size and try again. For the string type it is possible that +the same issue occurs again if the string has grown in the meantime. It is recommended to call &VIDIOC-QUERYCTRL; first and use <structfield>maximum</structfield>+1 as the new <structfield>size</structfield> value. It is guaranteed that that is sufficient memory. </para> + <para>N-dimensional arrays are set and retrieved row-by-row. You cannot set a partial +array, all elements have to be set or retrieved. The total size is calculated +as <structfield>elems</structfield> * <structfield>elem_size</structfield>. +These values can be obtained by calling &VIDIOC-QUERY-EXT-CTRL;.</para> + <para>To change the value of a set of controls applications initialize the <structfield>id</structfield>, <structfield>size</structfield>, <structfield>reserved2</structfield> and -<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +<structfield>value/value64/string/ptr</structfield> fields of each &v4l2-ext-control; and call the <constant>VIDIOC_S_EXT_CTRLS</constant> ioctl. The controls will only be set if <emphasis>all</emphasis> control values are valid.</para> @@ -96,7 +103,7 @@ valid.</para> <para>To check if a set of controls have correct values applications initialize the <structfield>id</structfield>, <structfield>size</structfield>, <structfield>reserved2</structfield> and -<structfield>value/string</structfield> fields of each &v4l2-ext-control; and +<structfield>value/value64/string/ptr</structfield> fields of each &v4l2-ext-control; and call the <constant>VIDIOC_TRY_EXT_CTRLS</constant> ioctl. It is up to the driver whether wrong values are automatically adjusted to a valid value or if an error is returned.</para> @@ -158,19 +165,47 @@ applications must set the array to zero.</entry> <entry></entry> <entry>__s32</entry> <entry><structfield>value</structfield></entry> - <entry>New value or current value.</entry> + <entry>New value or current value. Valid if this control is not of +type <constant>V4L2_CTRL_TYPE_INTEGER64</constant> and +<constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is not set.</entry> </row> <row> <entry></entry> <entry>__s64</entry> <entry><structfield>value64</structfield></entry> - <entry>New value or current value.</entry> + <entry>New value or current value. Valid if this control is of +type <constant>V4L2_CTRL_TYPE_INTEGER64</constant> and +<constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is not set.</entry> </row> <row> <entry></entry> <entry>char *</entry> <entry><structfield>string</structfield></entry> - <entry>A pointer to a string.</entry> + <entry>A pointer to a string. Valid if this control is of +type <constant>V4L2_CTRL_TYPE_STRING</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>__u8 *</entry> + <entry><structfield>p_u8</structfield></entry> + <entry>A pointer to a matrix control of unsigned 8-bit values. +Valid if this control is of type <constant>V4L2_CTRL_TYPE_U8</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>__u16 *</entry> + <entry><structfield>p_u16</structfield></entry> + <entry>A pointer to a matrix control of unsigned 16-bit values. +Valid if this control is of type <constant>V4L2_CTRL_TYPE_U16</constant>.</entry> + </row> + <row> + <entry></entry> + <entry>void *</entry> + <entry><structfield>ptr</structfield></entry> + <entry>A pointer to a compound type which can be an N-dimensional array and/or a +compound type (the control's type is >= <constant>V4L2_CTRL_COMPOUND_TYPES</constant>). +Valid if <constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is set for this control. +</entry> </row> </tbody> </tgroup> |