[media] v4l: v4l2_subdev userspace frame interval API
The three new ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL, VIDIOC_SUBDEV_G_FRAME_INTERVAL and VIDIOC_SUBDEV_S_FRAME_INTERVAL can be used to enumerate and configure a subdev's frame rate from userspace. Two new video::g/s_frame_interval subdev operations are introduced to support those ioctls. The existing video::g/s_parm operations are deprecated and shouldn't be used anymore. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Laurent Pinchart
committed by
Mauro Carvalho Chehab
Mauro Carvalho Chehab
parent
333c8b9778
commit
35c3017a29
@@ -507,9 +507,11 @@ and discussions on the V4L mailing list.</revremark>
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&sub-reqbufs;
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&sub-s-hw-freq-seek;
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&sub-streamon;
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&sub-subdev-enum-frame-interval;
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&sub-subdev-enum-frame-size;
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&sub-subdev-enum-mbus-code;
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&sub-subdev-g-fmt;
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&sub-subdev-g-frame-interval;
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&sub-subscribe-event;
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<!-- End of ioctls. -->
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&sub-mmap;
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152
Documentation/DocBook/v4l/vidioc-subdev-enum-frame-interval.xml
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152
Documentation/DocBook/v4l/vidioc-subdev-enum-frame-interval.xml
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@@ -0,0 +1,152 @@
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<refentry id="vidioc-subdev-enum-frame-interval">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</refname>
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<refpurpose>Enumerate frame intervals</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>struct v4l2_subdev_frame_interval_enum *
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<parameter>argp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>&fd;</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<note>
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<title>Experimental</title>
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<para>This is an <link linkend="experimental">experimental</link>
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interface and may change in the future.</para>
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</note>
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<para>This ioctl lets applications enumerate available frame intervals on a
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given sub-device pad. Frame intervals only makes sense for sub-devices that
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can control the frame period on their own. This includes, for instance,
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image sensors and TV tuners.</para>
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<para>For the common use case of image sensors, the frame intervals
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available on the sub-device output pad depend on the frame format and size
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on the same pad. Applications must thus specify the desired format and size
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when enumerating frame intervals.</para>
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<para>To enumerate frame intervals applications initialize the
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<structfield>index</structfield>, <structfield>pad</structfield>,
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<structfield>code</structfield>, <structfield>width</structfield> and
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<structfield>height</structfield> fields of
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&v4l2-subdev-frame-interval-enum; and call the
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<constant>VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL</constant> ioctl with a pointer
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to this structure. Drivers fill the rest of the structure or return
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an &EINVAL; if one of the input fields is invalid. All frame intervals are
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enumerable by beginning at index zero and incrementing by one until
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<errorcode>EINVAL</errorcode> is returned.</para>
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<para>Available frame intervals may depend on the current 'try' formats
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at other pads of the sub-device, as well as on the current active links. See
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&VIDIOC-SUBDEV-G-FMT; for more information about the try formats.</para>
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<para>Sub-devices that support the frame interval enumeration ioctl should
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implemented it on a single pad only. Its behaviour when supported on
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multiple pads of the same sub-device is not defined.</para>
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<table pgwide="1" frame="none" id="v4l2-subdev-frame-interval-enum">
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<title>struct <structname>v4l2_subdev_frame_interval_enum</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u32</entry>
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<entry><structfield>index</structfield></entry>
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<entry>Number of the format in the enumeration, set by the
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application.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>pad</structfield></entry>
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<entry>Pad number as reported by the media controller API.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>code</structfield></entry>
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<entry>The media bus format code, as defined in
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<xref linkend="v4l2-mbus-format" />.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>width</structfield></entry>
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<entry>Frame width, in pixels.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>height</structfield></entry>
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<entry>Frame height, in pixels.</entry>
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</row>
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<row>
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<entry>&v4l2-fract;</entry>
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<entry><structfield>interval</structfield></entry>
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<entry>Period, in seconds, between consecutive video frames.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[9]</entry>
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<entry>Reserved for future extensions. Applications and drivers must
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set the array to zero.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</refsect1>
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<refsect1>
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&return-value;
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<variablelist>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The &v4l2-subdev-frame-interval-enum;
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<structfield>pad</structfield> references a non-existing pad, one of
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the <structfield>code</structfield>, <structfield>width</structfield>
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or <structfield>height</structfield> fields are invalid for the given
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pad or the <structfield>index</structfield> field is out of bounds.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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</refentry>
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141
Documentation/DocBook/v4l/vidioc-subdev-g-frame-interval.xml
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141
Documentation/DocBook/v4l/vidioc-subdev-g-frame-interval.xml
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@@ -0,0 +1,141 @@
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<refentry id="vidioc-subdev-g-frame-interval">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_SUBDEV_G_FRAME_INTERVAL</refname>
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<refname>VIDIOC_SUBDEV_S_FRAME_INTERVAL</refname>
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<refpurpose>Get or set the frame interval on a subdev pad</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>struct v4l2_subdev_frame_interval *<parameter>argp</parameter>
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</paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>&fd;</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>VIDIOC_SUBDEV_G_FRAME_INTERVAL, VIDIOC_SUBDEV_S_FRAME_INTERVAL</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<note>
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<title>Experimental</title>
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<para>This is an <link linkend="experimental">experimental</link>
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interface and may change in the future.</para>
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</note>
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<para>These ioctls are used to get and set the frame interval at specific
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subdev pads in the image pipeline. The frame interval only makes sense for
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sub-devices that can control the frame period on their own. This includes,
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for instance, image sensors and TV tuners. Sub-devices that don't support
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frame intervals must not implement these ioctls.</para>
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<para>To retrieve the current frame interval applications set the
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<structfield>pad</structfield> field of a &v4l2-subdev-frame-interval; to
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the desired pad number as reported by the media controller API. When they
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call the <constant>VIDIOC_SUBDEV_G_FRAME_INTERVAL</constant> ioctl with a
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pointer to this structure the driver fills the members of the
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<structfield>interval</structfield> field.</para>
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<para>To change the current frame interval applications set both the
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<structfield>pad</structfield> field and all members of the
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<structfield>interval</structfield> field. When they call the
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<constant>VIDIOC_SUBDEV_S_FRAME_INTERVAL</constant> ioctl with a pointer to
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this structure the driver verifies the requested interval, adjusts it based
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on the hardware capabilities and configures the device. Upon return the
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&v4l2-subdev-frame-interval; contains the current frame interval as would be
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returned by a <constant>VIDIOC_SUBDEV_G_FRAME_INTERVAL</constant> call.
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</para>
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<para>Drivers must not return an error solely because the requested interval
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doesn't match the device capabilities. They must instead modify the interval
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to match what the hardware can provide. The modified interval should be as
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close as possible to the original request.</para>
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<para>Sub-devices that support the frame interval ioctls should implement
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them on a single pad only. Their behaviour when supported on multiple pads
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of the same sub-device is not defined.</para>
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<table pgwide="1" frame="none" id="v4l2-subdev-frame-interval">
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<title>struct <structname>v4l2_subdev_frame_interval</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u32</entry>
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<entry><structfield>pad</structfield></entry>
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<entry>Pad number as reported by the media controller API.</entry>
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</row>
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<row>
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<entry>&v4l2-fract;</entry>
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<entry><structfield>interval</structfield></entry>
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<entry>Period, in seconds, between consecutive video frames.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[9]</entry>
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<entry>Reserved for future extensions. Applications and drivers must
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set the array to zero.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</refsect1>
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<refsect1>
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&return-value;
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<variablelist>
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<varlistentry>
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<term><errorcode>EBUSY</errorcode></term>
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<listitem>
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<para>The frame interval can't be changed because the pad is currently
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busy. This can be caused, for instance, by an active video stream on
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the pad. The ioctl must not be retried without performing another
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action to fix the problem first. Only returned by
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<constant>VIDIOC_SUBDEV_S_FRAME_INTERVAL</constant></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The &v4l2-subdev-frame-interval; <structfield>pad</structfield>
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references a non-existing pad, or the pad doesn't support frame
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intervals.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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</refentry>
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