diff options
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/media/dvb/frontend.xml | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/Documentation/DocBook/media/dvb/frontend.xml b/Documentation/DocBook/media/dvb/frontend.xml index b1f01239d4da..086e62bcad11 100644 --- a/Documentation/DocBook/media/dvb/frontend.xml +++ b/Documentation/DocBook/media/dvb/frontend.xml @@ -221,8 +221,20 @@ by</para> <section id="dvb-frontend-parameters"> <title>frontend parameters</title> <para>The kind of parameters passed to the frontend device for tuning depend on -the kind of hardware you are using. All kinds of parameters are combined as an -union in the FrontendParameters structure:</para> +the kind of hardware you are using.</para> +<para>The struct <constant>dvb_frontend_parameters</constant> uses an +union with specific per-system parameters. However, as newer delivery systems +required more data, the structure size weren't enough to fit, and just +extending its size would break the existing applications. So, those parameters +were replaced by the usage of <link linkend="FE_GET_SET_PROPERTY"> +<constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> ioctl's. The +new API is flexible enough to add new parameters to existing delivery systems, +and to add newer delivery systems.</para> +<para>So, newer applications should use <link linkend="FE_GET_SET_PROPERTY"> +<constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> instead, in +order to be able to support the newer System Delivery like DVB-S2, DVB-T2, +DVB-C2, ISDB, etc.</para> +<para>All kinds of parameters are combined as an union in the FrontendParameters structure:</para> <programlisting> struct dvb_frontend_parameters { uint32_t frequency; /⋆ (absolute) frequency in Hz for QAM/OFDM ⋆/ |