mirror of https://gitee.com/openkylin/linux.git
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>
This commit is contained in:
Hans Verkuil
Mauro Carvalho Chehab
parent
226c0eeaea
commit
f44026dbe4
|
|
@ -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
|
||||
|
|
@ -65,13 +69,6 @@ not compatible with V4L or V4L2.</para> </footnote>,
|
|||
<filename>/dev/radio63</filename></para></entry>
|
||||
<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>,
|
||||
|
|
@ -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>
|
||||
|
|
|
|||
|
|
@ -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:
|
||||
|
|
|
|||
|
|
@ -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>
|
||||
|
|
@ -110,9 +111,16 @@ 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>
|
||||
|
|
|
|||
|
|
@ -498,29 +498,6 @@ When: April 2011
|
|||
Why: Superseded by xt_CT
|
||||
Who: Netfilter developer team <netfilter-devel@vger.kernel.org>
|
||||
|
||||
---------------------------
|
||||
|
||||
What: video4linux /dev/vtx teletext API support
|
||||
When: 2.6.35
|
||||
Files: drivers/media/video/saa5246a.c drivers/media/video/saa5249.c
|
||||
include/linux/videotext.h
|
||||
Why: The vtx device nodes have been superseded by vbi device nodes
|
||||
for many years. No applications exist that use the vtx support.
|
||||
Of the two i2c drivers that actually support this API the saa5249
|
||||
has been impossible to use for a year now and no known hardware
|
||||
that supports this device exists. The saa5246a is theoretically
|
||||
supported by the old mxb boards, but it never actually worked.
|
||||
|
||||
In summary: there is no hardware that can use this API and there
|
||||
are no applications actually implementing this API.
|
||||
|
||||
The vtx support still reserves minors 192-223 and we would really
|
||||
like to reuse those for upcoming new functionality. In the unlikely
|
||||
event that new hardware appears that wants to use the functionality
|
||||
provided by the vtx API, then that functionality should be build
|
||||
around the sliced VBI API instead.
|
||||
Who: Hans Verkuil <hverkuil@xs4all.nl>
|
||||
|
||||
----------------------------
|
||||
|
||||
What: IRQF_DISABLED
|
||||
|
|
|
|||
|
|
@ -278,7 +278,6 @@ Code Seq#(hex) Include File Comments
|
|||
<mailto:oe@port.de>
|
||||
'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
|
||||
0x80 00-1F linux/fb.h
|
||||
0x81 00-1F linux/videotext.h
|
||||
0x88 00-3F media/ovcamchip.h
|
||||
0x89 00-06 arch/x86/include/asm/sockios.h
|
||||
0x89 0B-DF linux/sockios.h
|
||||
|
|
|
|||
|
|
@ -19,7 +19,6 @@ function makedev () {
|
|||
echo "*** new device names ***"
|
||||
makedev video 0
|
||||
makedev radio 64
|
||||
makedev vtx 192
|
||||
makedev vbi 224
|
||||
|
||||
#echo "*** old device names (for compatibility only) ***"
|
||||
|
|
|
|||
|
|
@ -44,8 +44,8 @@ All drivers have the following structure:
|
|||
|
||||
2) A way of initializing and commanding sub-devices (if any).
|
||||
|
||||
3) Creating V4L2 device nodes (/dev/videoX, /dev/vbiX, /dev/radioX and
|
||||
/dev/vtxX) and keeping track of device-node specific data.
|
||||
3) Creating V4L2 device nodes (/dev/videoX, /dev/vbiX and /dev/radioX)
|
||||
and keeping track of device-node specific data.
|
||||
|
||||
4) Filehandle-specific structs containing per-filehandle data;
|
||||
|
||||
|
|
@ -488,7 +488,6 @@ types exist:
|
|||
VFL_TYPE_GRABBER: videoX for video input/output devices
|
||||
VFL_TYPE_VBI: vbiX for vertical blank data (i.e. closed captions, teletext)
|
||||
VFL_TYPE_RADIO: radioX for radio tuners
|
||||
VFL_TYPE_VTX: vtxX for teletext devices (deprecated, don't use)
|
||||
|
||||
The last argument gives you a certain amount of control over the device
|
||||
device node number used (i.e. the X in videoX). Normally you will pass -1
|
||||
|
|
|
|||
Loading…
Reference in New Issue