+++ /dev/null
-<refentry id="vidioc-g-edid">
- <refmeta>
- <refentrytitle>ioctl VIDIOC_G_EDID, VIDIOC_S_EDID, VIDIOC_SUBDEV_G_EDID, VIDIOC_SUBDEV_S_EDID</refentrytitle>
- &manvol;
- </refmeta>
-
- <refnamediv>
- <refname>VIDIOC_G_EDID</refname>
- <refname>VIDIOC_S_EDID</refname>
- <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_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>struct v4l2_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_G_EDID, VIDIOC_S_EDID, 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
- from a receiver or an output of a transmitter device. They can be
- used with subdevice nodes (/dev/v4l-subdevX) or with video nodes (/dev/videoX).</para>
-
- <para>When used with video nodes the <structfield>pad</structfield> field represents the
- input (for video capture devices) or output (for video output devices) index as
- is returned by &VIDIOC-ENUMINPUT; and &VIDIOC-ENUMOUTPUT; respectively. When used
- with subdevice nodes the <structfield>pad</structfield> field represents the
- input or output pad of the subdevice. If there is no EDID support for the given
- <structfield>pad</structfield> value, then the &EINVAL; will be returned.</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, zero the <structfield>reserved</structfield> array and call
- <constant>VIDIOC_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> * 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>If <structfield>start_block</structfield> and <structfield>blocks</structfield> are
- both set to 0 when <constant>VIDIOC_G_EDID</constant> is called, then the driver will
- set <structfield>blocks</structfield> to the total number of available EDID blocks
- and it will return 0 without copying any data. This is an easy way to discover how many
- EDID blocks there are. Note that if there are no EDID blocks available at all, then
- the driver will set <structfield>blocks</structfield> to 0 and it returns 0.</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, set
- <structfield>start_block</structfield> to 0 and zero the <structfield>reserved</structfield> array.
- 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-edid">
- <title>struct <structname>v4l2_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. When used with a video device
- node the pad represents the input or output index as returned by
- &VIDIOC-ENUMINPUT; and &VIDIOC-ENUMOUTPUT; respectively.</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>__u32</entry>
- <entry><structfield>reserved</structfield>[5]</entry>
- <entry>Reserved for future extensions. Applications and drivers must
- set the array to zero.</entry>
- </row>
- <row>
- <entry>__u8 *</entry>
- <entry><structfield>edid</structfield></entry>
- <entry>Pointer to memory that contains the EDID. The minimum size is
- <structfield>blocks</structfield> * 128.</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>
projects / mirror_ubuntu-zesty-kernel.git / blobdiff