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authorFrederic Weisbecker <fweisbec@gmail.com>2009-10-18 01:09:09 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2009-10-18 01:12:33 +0200
commit0f8f86c7bdd1c954fbe153af437a0d91a6c5721a (patch)
tree94a8d419a470a4f9852ca397bb9bbe48db92ff5c /Documentation/DocBook/v4l/dev-teletext.xml
parentMerge branch 'linus' into tracing/hw-breakpoints (diff)
parentperf tools: Move dereference after NULL test (diff)
downloadlinux-dev-0f8f86c7bdd1c954fbe153af437a0d91a6c5721a.tar.xz
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Merge commit 'perf/core' into perf/hw-breakpoint
Conflicts: kernel/Makefile kernel/trace/Makefile kernel/trace/trace.h samples/Makefile Merge reason: We need to be uptodate with the perf events development branch because we plan to rewrite the breakpoints API on top of perf events.
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+ <title>Teletext Interface</title>
+
+ <para>This interface aims 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
+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
+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>
+
+ <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>
+
+ <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>
+
+ <!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+ -->