[media] dvb: Allow select between DVB-C Annex A and Annex C

DVB-C, as defined by ITU-T J.83 has 3 annexes. The differences between
Annex A and Annex C is that Annex C uses a subset of the modulation
types, and uses a different rolloff factor. A different rolloff means
that the bandwidth required is slicely different, and may affect the
saw filter configuration at the tuners. Also, some demods have different
configurations, depending on using Annex A or Annex C.

So, allow userspace to specify it, by changing the rolloff factor.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/DocBook/media/dvb/dvbproperty.xml b/Documentation/DocBook/media/dvb/dvbproperty.xml
index 3bc8a61efe30..6ac803959a47 100644
--- a/Documentation/DocBook/media/dvb/dvbproperty.xml
+++ b/Documentation/DocBook/media/dvb/dvbproperty.xml
@@ -311,6 +311,8 @@ typedef enum fe_rolloff {
         ROLLOFF_20,
         ROLLOFF_25,
         ROLLOFF_AUTO,
+        ROLLOFF_15, /* DVB-C Annex A */
+        ROLLOFF_13, /* DVB-C Annex C */
 } fe_rolloff_t;
                 </programlisting>
                 </section>
@@ -778,8 +780,10 @@ typedef enum fe_hierarchy {
                         <listitem><para><link linkend="DTV-MODULATION"><constant>DTV_MODULATION</constant></link></para></listitem>
                         <listitem><para><link linkend="DTV-INVERSION"><constant>DTV_INVERSION</constant></link></para></listitem>
                         <listitem><para><link linkend="DTV-SYMBOL-RATE"><constant>DTV_SYMBOL_RATE</constant></link></para></listitem>
+                        <listitem><para><link linkend="DTV-ROLLOFF"><constant>DTV_ROLLOFF</constant></link></para></listitem>
                         <listitem><para><link linkend="DTV-INNER-FEC"><constant>DTV_INNER_FEC</constant></link></para></listitem>
                 </itemizedlist>
+                <para>The Rolloff of 0.15 (ROLLOFF_15) is assumed, as ITU-T J.83 Annex A is more common. For Annex C, rolloff should be 0.13 (ROLLOFF_13). All other values are invalid.</para>
         </section>
         <section id="dvbc-annex-b-params">
                 <title>DVB-C Annex B delivery system</title>