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[media] DocBook: Provide a high-level description for DVB frontend 

Instead of just showing ioctls, let's add an introdutory text
briefly explaining the DVB frontend API.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Mauro Carvalho Chehab 2015-05-28 14:45:17 -03:00
parent d27518ca0c
commit be1ad6e76e
1 changed files with 16 additions and 6 deletions
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22
Documentation/DocBook/media/dvb/frontend.xml
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@ -29,19 +29,29 @@
specification is available at
<ulink url="http://www.eutelsat.com/satellites/4_5_5.html">Eutelsat</ulink>.</para>
<section id="query-dvb-frontend-info">
<title>Querying frontend information</title>
<para>Information about the frontend can be queried with
<link linkend="FE_GET_INFO">FE_GET_INFO</link>.</para>
<para>Usually, the first thing to do when the frontend is opened is to
check the frontend capabilities. This is done using <link linkend="FE_GET_INFO">FE_GET_INFO</link>. This ioctl will enumerate
the DVB API version and other characteristics about the frontend, and
can be opened either in read only or read/write mode.</para>
</section>
<section id="dvb-fe-read-status">
<title>Querying frontend status</title>
<title>Querying frontend status and statistics</title>
<para>Information about the frontend tuner locking status can be queried with
<link linkend="FE_READ_STATUS">FE_READ_STATUS</link>.</para>
<para>Once <link linkend="FE_GET_PROPERTY"><constant>FE_SET_PROPERTY</constant></link>
is called, the frontend will run a kernel thread that will periodically
check for the tuner lock status and provide statistics about the quality
of the signal.</para>
<para>The information about the frontend tuner locking status can be queried
using <link linkend="FE_READ_STATUS">FE_READ_STATUS</link>.</para>
<para>Signal statistics are provided via <link linkend="FE_GET_PROPERTY"><constant>FE_GET_PROPERTY</constant></link>.
Please notice that several statistics require the demodulator to be fully
locked (e. g. with FE_HAS_LOCK bit set). See
<xref linkend="frontend-stat-properties">Frontend statistics indicators</xref>
for more details.</para>
</section>
&sub-dvbproperty;