From 2d8a337add332f8a4265df174edad40bb71e8071 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 6 Aug 2010 12:52:43 -0300 Subject: 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 Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/v4l/compat.xml | 24 ++++++++++++++++-------- Documentation/DocBook/v4l/dev-teletext.xml | 29 +++++++++++++---------------- Documentation/DocBook/v4l/v4l2.xml | 10 +++++++++- 3 files changed, 38 insertions(+), 25 deletions(-) (limited to 'Documentation/DocBook') diff --git a/Documentation/DocBook/v4l/compat.xml b/Documentation/DocBook/v4l/compat.xml index 54447f0d0784..c9ce61d981f5 100644 --- a/Documentation/DocBook/v4l/compat.xml +++ b/Documentation/DocBook/v4l/compat.xml @@ -21,11 +21,15 @@ API. Opening and Closing Devices 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 and below in . + 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. + The V4L videodev 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. , /dev/radio63 64-127 - - Teletext decoder - /dev/vtx, -/dev/vtx0 to -/dev/vtx31 - 192-223 - Raw VBI capture /dev/vbi, @@ -2345,6 +2342,17 @@ more information. +
+ V4L2 in Linux 2.6.37 + + + 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. + + + +
Relation of V4L2 to other Linux multimedia APIs diff --git a/Documentation/DocBook/v4l/dev-teletext.xml b/Documentation/DocBook/v4l/dev-teletext.xml index 76184e8ed618..414b1cfff9f4 100644 --- a/Documentation/DocBook/v4l/dev-teletext.xml +++ b/Documentation/DocBook/v4l/dev-teletext.xml @@ -1,35 +1,32 @@ Teletext Interface - This interface aims at devices receiving and demodulating + This interface was aimed at devices receiving and demodulating Teletext data [, ], evaluating the Teletext packages and storing formatted pages in cache memory. Such devices are usually implemented as microcontrollers with serial -interface (I2C) and can be found on older +interface (I2C) and could be found on old TV cards, dedicated Teletext decoding cards and home-brew devices connected to the PC parallel port. - The Teletext API was designed by Martin Buck. It is defined in + The Teletext API was designed by Martin Buck. It was defined in the kernel header file linux/videotext.h, the specification is available from ftp://ftp.gwdg.de/pub/linux/misc/videotext/. (Videotext is the name of -the German public television Teletext service.) Conventional character -device file names are /dev/vtx and -/dev/vttuner, 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 -/dev/tlkN, device number 102, N. +the German public television Teletext service.) Eventually the Teletext API was integrated into the V4L API with character device file names /dev/vtx0 to /dev/vtx31, 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. +192 to 223. - 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. + 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. + + Modern devices all use the raw or +sliced VBI API. + + 2.6.37 + 2010-08-06 + hv + Removed obsolete vtx (videotext) API. + + 2.6.33 2009-12-03 -- cgit v1.2.3