[mythtv-users] DVB-S locking problem

Lawrence Rust lvr at softsystem.co.uk
Sun Dec 4 12:54:08 UTC 2011


On Sat, 2011-12-03 at 16:54 -0500, Michael T. Dean wrote:
> On 12/03/2011 04:07 AM, Mark Carbonaro wrote:
> > I have a strange issue that started happening in the last month and
> > was wondering if anyone has some advice on how I can track down and
> > resolve the issue.
> >
> > I use a DVB-S (Tevii S660) which was working fine, but all of a sudden
> > it stopped getting a lock (Tl___).
> ...
> > I am running the following:
> > mythbackend version: fixes/0.24 [v0.24.1-101-g5da2367]
> > Linux Kernel Gentoo 3.0.6 (I have also tried running 2.6.39 kernel as
> > it seemed to stop working around the time I upgraded, but no luck)
> 
> Lawrence, could this be related to your ticket at:
> 
> http://code.mythtv.org/trac/ticket/10153
> 
> (as the Tevii S660 is actually a DVB-S2 device)?

Maybe it's time that a fix for this bug is implemented.  I got a mail
from Mauro Carvalho Chehab this week saying that he didn't regard this
as a Linux media bug.  So the solution is solely with MythTV.  FYI I use
the following patch:

--- a/mythtv/libs/libmythtv/dtvmultiplex.cpp
+++ b/mythtv/libs/libmythtv/dtvmultiplex.cpp
@@ -262,6 +262,24 @@ bool DTVMultiplex::ParseDVB_S2(
         return false;
     }
 
+    switch (static_cast<int>(mod_sys))
+    {
+    case DTVModulationSystem::kModulationSystem_UNDEFINED:
+        // Force dvb-s if using qpsk
+        if (DTVModulation::kModulationQPSK == modulation)
+            mod_sys = DTVModulationSystem::kModulationSystem_DVBS;
+        else
+            mod_sys = DTVModulationSystem::kModulationSystem_DVBS2;
+        break;
+    case DTVModulationSystem::kModulationSystem_DVBS:
+    case DTVModulationSystem::kModulationSystem_DVBS2:
+        break;
+    default:
+        LOG(VB_GENERAL, LOG_ERR, LOC + "Unsupported S2 modulation system " +
+                QString("parameter '%1', aborting.").arg(_mod_sys));
+        return false;
+    }
+
     if (!_rolloff.isEmpty())
         ok &= rolloff.Parse(_rolloff);

Or is this patch too big as well?

-- 
Lawrence


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