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authorHans Verkuil <hverkuil@xs4all.nl>2010-08-06 12:52:43 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2010-10-21 01:05:48 -0200
commitf44026dbe42d38f2e2dfdc7bf35cafc7e44794d7 (patch)
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parent226c0eeaea6732c686a5f4e06f25e5850cd5dd61 (diff)
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V4L/DVB: Documentation: update now that the vtx/videotext API has been removed
Remove all references to /dev/vtx in the documentation, except for some historical comments in dev-teletext.xml. Documentation/devices.txt is not updated, this will go through Alan Cox who maintains this file. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/v4l/compat.xml24
-rw-r--r--Documentation/DocBook/v4l/dev-teletext.xml29
-rw-r--r--Documentation/DocBook/v4l/v4l2.xml10
3 files changed, 38 insertions, 25 deletions
diff --git a/Documentation/DocBook/v4l/compat.xml b/Documentation/DocBook/v4l/compat.xml
index 54447f0..c9ce61d 100644
--- a/Documentation/DocBook/v4l/compat.xml
+++ b/Documentation/DocBook/v4l/compat.xml
@@ -21,11 +21,15 @@ API.</para>
<title>Opening and Closing Devices</title>
<para>For compatibility reasons the character device file names
-recommended for V4L2 video capture, overlay, radio, teletext and raw
+recommended for V4L2 video capture, overlay, radio and raw
vbi capture devices did not change from those used by V4L. They are
listed in <xref linkend="devices" /> and below in <xref
linkend="v4l-dev" />.</para>
+ <para>The teletext devices (minor range 192-223) have been removed in
+V4L2 and no longer exist. There is no hardware available anymore for handling
+pure teletext. Instead raw or sliced VBI is used.</para>
+
<para>The V4L <filename>videodev</filename> module automatically
assigns minor numbers to drivers in load order, depending on the
registered device type. We recommend that V4L2 drivers by default
@@ -66,13 +70,6 @@ not compatible with V4L or V4L2.</para> </footnote>,
<entry>64-127</entry>
</row>
<row>
- <entry>Teletext decoder</entry>
- <entry><para><filename>/dev/vtx</filename>,
-<filename>/dev/vtx0</filename> to
-<filename>/dev/vtx31</filename></para></entry>
- <entry>192-223</entry>
- </row>
- <row>
<entry>Raw VBI capture</entry>
<entry><para><filename>/dev/vbi</filename>,
<filename>/dev/vbi0</filename> to
@@ -2345,6 +2342,17 @@ more information.</para>
</listitem>
</orderedlist>
</section>
+ <section>
+ <title>V4L2 in Linux 2.6.37</title>
+ <orderedlist>
+ <listitem>
+ <para>Remove the vtx (videotext/teletext) API. This API was no longer
+used and no hardware exists to verify the API. Nor were any userspace applications found
+that used it. It was originally scheduled for removal in 2.6.35.
+ </para>
+ </listitem>
+ </orderedlist>
+ </section>
<section id="other">
<title>Relation of V4L2 to other Linux multimedia APIs</title>
diff --git a/Documentation/DocBook/v4l/dev-teletext.xml b/Documentation/DocBook/v4l/dev-teletext.xml
index 76184e8..414b1cf 100644
--- a/Documentation/DocBook/v4l/dev-teletext.xml
+++ b/Documentation/DocBook/v4l/dev-teletext.xml
@@ -1,35 +1,32 @@
<title>Teletext Interface</title>
- <para>This interface aims at devices receiving and demodulating
+ <para>This interface was aimed at devices receiving and demodulating
Teletext data [<xref linkend="ets300706" />, <xref linkend="itu653" />], evaluating the
Teletext packages and storing formatted pages in cache memory. Such
devices are usually implemented as microcontrollers with serial
-interface (I<superscript>2</superscript>C) and can be found on older
+interface (I<superscript>2</superscript>C) and could be found on old
TV cards, dedicated Teletext decoding cards and home-brew devices
connected to the PC parallel port.</para>
- <para>The Teletext API was designed by Martin Buck. It is defined in
+ <para>The Teletext API was designed by Martin Buck. It was defined in
the kernel header file <filename>linux/videotext.h</filename>, the
specification is available from <ulink url="ftp://ftp.gwdg.de/pub/linux/misc/videotext/">
ftp://ftp.gwdg.de/pub/linux/misc/videotext/</ulink>. (Videotext is the name of
-the German public television Teletext service.) Conventional character
-device file names are <filename>/dev/vtx</filename> and
-<filename>/dev/vttuner</filename>, with device number 83, 0 and 83, 16
-respectively. A similar interface exists for the Philips SAA5249
-Teletext decoder [specification?] with character device file names
-<filename>/dev/tlkN</filename>, device number 102, N.</para>
+the German public television Teletext service.)</para>
<para>Eventually the Teletext API was integrated into the V4L API
with character device file names <filename>/dev/vtx0</filename> to
<filename>/dev/vtx31</filename>, device major number 81, minor numbers
-192 to 223. For reference the V4L Teletext API specification is
-reproduced here in full: "Teletext interfaces talk the existing VTX
-API." Teletext devices with major number 83 and 102 will be removed in
-Linux 2.6.</para>
+192 to 223.</para>
- <para>There are no plans to replace the Teletext API or to integrate
-it into V4L2. Please write to the linux-media mailing list: &v4l-ml;
-when the need arises.</para>
+ <para>However, teletext decoders were quickly replaced by more
+generic VBI demodulators and those dedicated teletext decoders no longer exist.
+For many years the vtx devices were still around, even though nobody used
+them. So the decision was made to finally remove support for the Teletext API in
+kernel 2.6.37.</para>
+
+ <para>Modern devices all use the <link linkend="raw-vbi">raw</link> or
+<link linkend="sliced">sliced</link> VBI API.</para>
<!--
Local Variables:
diff --git a/Documentation/DocBook/v4l/v4l2.xml b/Documentation/DocBook/v4l/v4l2.xml
index 7c3c098..839e93e 100644
--- a/Documentation/DocBook/v4l/v4l2.xml
+++ b/Documentation/DocBook/v4l/v4l2.xml
@@ -99,6 +99,7 @@ Remote Controller chapter.</contrib>
<year>2007</year>
<year>2008</year>
<year>2009</year>
+ <year>2010</year>
<holder>Bill Dirks, Michael H. Schimek, Hans Verkuil, Martin
Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab</holder>
</copyright>
@@ -110,10 +111,17 @@ Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab</holder>
<!-- Put document revisions here, newest first. -->
<!-- API revisions (changes and additions of defines, enums,
structs, ioctls) must be noted in more detail in the history chapter
-(compat.sgml), along with the possible impact on existing drivers and
+(compat.xml), along with the possible impact on existing drivers and
applications. -->
<revision>
+ <revnumber>2.6.37</revnumber>
+ <date>2010-08-06</date>
+ <authorinitials>hv</authorinitials>
+ <revremark>Removed obsolete vtx (videotext) API.</revremark>
+ </revision>
+
+ <revision>
<revnumber>2.6.33</revnumber>
<date>2009-12-03</date>
<authorinitials>mk</authorinitials>