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+<refentry id="vidioc-subdev-g-edid">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_SUBDEV_G_EDID</refname>
+ <refname>VIDIOC_SUBDEV_S_EDID</refname>
+ <refpurpose>Get or set the EDID of a video receiver/transmitter</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>int <function>ioctl</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>int <parameter>request</parameter></paramdef>
+ <paramdef>struct v4l2_subdev_edid *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>int <function>ioctl</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>int <parameter>request</parameter></paramdef>
+ <paramdef>const struct v4l2_subdev_edid *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>fd</parameter></term>
+ <listitem>
+ <para>&fd;</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>request</parameter></term>
+ <listitem>
+ <para>VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para></para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+ <para>These ioctls can be used to get or set an EDID associated with an input pad
+ from a receiver or an output pad of a transmitter subdevice.</para>
+
+ <para>To get the EDID data the application has to fill in the <structfield>pad</structfield>,
+ <structfield>start_block</structfield>, <structfield>blocks</structfield> and <structfield>edid</structfield>
+ fields and call <constant>VIDIOC_SUBDEV_G_EDID</constant>. The current EDID from block
+ <structfield>start_block</structfield> and of size <structfield>blocks</structfield>
+ will be placed in the memory <structfield>edid</structfield> points to. The <structfield>edid</structfield>
+ pointer must point to memory at least <structfield>blocks</structfield>&nbsp;*&nbsp;128 bytes
+ large (the size of one block is 128 bytes).</para>
+
+ <para>If there are fewer blocks than specified, then the driver will set <structfield>blocks</structfield>
+ to the actual number of blocks. If there are no EDID blocks available at all, then the error code
+ ENODATA is set.</para>
+
+ <para>If blocks have to be retrieved from the sink, then this call will block until they
+ have been read.</para>
+
+ <para>To set the EDID blocks of a receiver the application has to fill in the <structfield>pad</structfield>,
+ <structfield>blocks</structfield> and <structfield>edid</structfield> fields and set
+ <structfield>start_block</structfield> to 0. It is not possible to set part of an EDID,
+ it is always all or nothing. Setting the EDID data is only valid for receivers as it makes
+ no sense for a transmitter.</para>
+
+ <para>The driver assumes that the full EDID is passed in. If there are more EDID blocks than
+ the hardware can handle then the EDID is not written, but instead the error code E2BIG is set
+ and <structfield>blocks</structfield> is set to the maximum that the hardware supports.
+ If <structfield>start_block</structfield> is any
+ value other than 0 then the error code EINVAL is set.</para>
+
+ <para>To disable an EDID you set <structfield>blocks</structfield> to 0. Depending on the
+ hardware this will drive the hotplug pin low and/or block the source from reading the EDID
+ data in some way. In any case, the end result is the same: the EDID is no longer available.
+ </para>
+
+ <table pgwide="1" frame="none" id="v4l2-subdev-edid">
+ <title>struct <structname>v4l2_subdev_edid</structname></title>
+ <tgroup cols="3">
+ &cs-str;
+ <tbody valign="top">
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>pad</structfield></entry>
+ <entry>Pad for which to get/set the EDID blocks.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>start_block</structfield></entry>
+ <entry>Read the EDID from starting with this block. Must be 0 when setting
+ the EDID.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>blocks</structfield></entry>
+ <entry>The number of blocks to get or set. Must be less or equal to 256 (the
+ maximum number of blocks as defined by the standard). When you set the EDID and
+ <structfield>blocks</structfield> is 0, then the EDID is disabled or erased.</entry>
+ </row>
+ <row>
+ <entry>__u8&nbsp;*</entry>
+ <entry><structfield>edid</structfield></entry>
+ <entry>Pointer to memory that contains the EDID. The minimum size is
+ <structfield>blocks</structfield>&nbsp;*&nbsp;128.</entry>
+ </row>
+ <row>
+ <entry>__u32</entry>
+ <entry><structfield>reserved</structfield>[5]</entry>
+ <entry>Reserved for future extensions. Applications and drivers must
+ set the array to zero.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>ENODATA</errorcode></term>
+ <listitem>
+ <para>The EDID data is not available.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><errorcode>E2BIG</errorcode></term>
+ <listitem>
+ <para>The EDID data you provided is more than the hardware can handle.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>