From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Document the support for the new complex type controls.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
.../DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 43 ++++++++++++++++++----
1 file changed, 35 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 b3bb957..d946d6b 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 complex types (<constant>V4L2_CTRL_FLAG_IS_PTR</constant> is set)
+must set the <structfield>p</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>Matrices are set and retrieved row-by-row. You cannot set a partial
+matrix, all elements have to be set or retrieved. The total size is calculated
+as <structfield>rows</structfield> * <structfield>cols</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/p</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>
@@ -96,11 +103,17 @@ 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/p</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>
+ <para>For matrices it is possible to only set or check only the first
+<constant>X</constant> elements by setting size to <constant>X * elem_size</constant>,
+where <structfield>elem_size</structfield> is obtained by calling &VIDIOC-QUERY-EXT-CTRL;.
+Matrix elements are set row-by-row. Matrix elements that are not explicitly
+set will be initialized to their default value.</para>
+
<para>When the <structfield>id</structfield> or
<structfield>ctrl_class</structfield> is invalid drivers return an
&EINVAL;. When the value is out of bounds drivers can choose to take
@@ -158,19 +171,33 @@ 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_IS_PTR</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_IS_PTR</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>void *</entry>
+ <entry><structfield>p</structfield></entry>
+ <entry>A pointer to a complex type which can be a matrix and/or a
+complex type (the control's type is >= <constant>V4L2_CTRL_COMPLEX_TYPES</constant>).
+Valid if <constant>V4L2_CTRL_FLAG_IS_PTR</constant> is set for this control.
+</entry>
</row>
</tbody>
</tgroup>
--
1.8.4.rc3
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