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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-edid.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-g-edid.xml b/Documentation/DocBook/media/v4l/vidioc-g-edid.xml new file mode 100644 index 00000000000..ce4563b8713 --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-g-edid.xml @@ -0,0 +1,162 @@ +<refentry id="vidioc-g-edid"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_EDID, VIDIOC_S_EDID</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_EDID</refname> + <refname>VIDIOC_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>const 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</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 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>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-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>__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> + <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> |