diff options
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-queryctrl.xml')
| -rw-r--r-- | Documentation/DocBook/v4l/vidioc-queryctrl.xml | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/v4l/vidioc-queryctrl.xml index 8e0e055ac93..0d5e8283cf3 100644 --- a/Documentation/DocBook/v4l/vidioc-queryctrl.xml +++ b/Documentation/DocBook/v4l/vidioc-queryctrl.xml @@ -103,8 +103,12 @@ structure. The driver fills the rest of the structure or returns an <structfield>index</structfield> is invalid. Menu items are enumerated by calling <constant>VIDIOC_QUERYMENU</constant> with successive <structfield>index</structfield> values from &v4l2-queryctrl; -<structfield>minimum</structfield> (0) to -<structfield>maximum</structfield>, inclusive.</para> +<structfield>minimum</structfield> to +<structfield>maximum</structfield>, inclusive. Note that it is possible +for <constant>VIDIOC_QUERYMENU</constant> to return an &EINVAL; for some +indices between <structfield>minimum</structfield> and <structfield>maximum</structfield>. +In that case that particular menu item is not supported by this driver. Also note that +the <structfield>minimum</structfield> value is not necessarily 0.</para> <para>See also the examples in <xref linkend="control" />.</para> @@ -139,7 +143,7 @@ string. This information is intended for the user.</entry> <entry><structfield>minimum</structfield></entry> <entry>Minimum value, inclusive. This field gives a lower bound for <constant>V4L2_CTRL_TYPE_INTEGER</constant> controls and the -lowest valid index (always 0) for <constant>V4L2_CTRL_TYPE_MENU</constant> controls. +lowest valid index for <constant>V4L2_CTRL_TYPE_MENU</constant> controls. For <constant>V4L2_CTRL_TYPE_STRING</constant> controls the minimum value gives the minimum length of the string. This length <emphasis>does not include the terminating zero</emphasis>. It may not be valid for any other type of control, including @@ -279,7 +283,7 @@ values which are actually different on the hardware.</entry> </row> <row> <entry><constant>V4L2_CTRL_TYPE_MENU</constant></entry> - <entry>0</entry> + <entry>≥ 0</entry> <entry>1</entry> <entry>N-1</entry> <entry>The control has a menu of N choices. The names of @@ -405,8 +409,10 @@ writing a value will cause the device to carry out a given action <term><errorcode>EINVAL</errorcode></term> <listitem> <para>The &v4l2-queryctrl; <structfield>id</structfield> -is invalid. The &v4l2-querymenu; <structfield>id</structfield> or -<structfield>index</structfield> is invalid.</para> +is invalid. The &v4l2-querymenu; <structfield>id</structfield> is +invalid or <structfield>index</structfield> is out of range (less than +<structfield>minimum</structfield> or greater than <structfield>maximum</structfield>) +or this particular menu item is not supported by the driver.</para> </listitem> </varlistentry> <varlistentry> |