[linux-dvb] Re: Channel switching

["Reiner Rosin" <r_rosin@hotmail.com>]

Hi Klaus,

first of all I have this problem too and tried your program, at least
every 15th switching caused an channel not sync error. But within my
short test (about 10 minutes) the sw was able to tune in with one or
two retries. I also applied the patch you suggested and it got even
worse, still switching problems but sometimes the program wasn't able
at all to tune to a channel (every 50th switching). And at the end
of my test the program failed due to a resource or device busy error!
So no success with this patch ...
That's what I've expected, because the main channel-switching problem
I've got here is switching from h to v pol. or vice versa. This could
be a power-problem (dvbs-card, lnbs, ...). So a question to the
driver developers: Is it possible to activate a function like +1V for
the 18V-power of the dvbs-card???
And to anybody out there: Who is able to run klaus' test program without
the patch without ANY channel-not-sync error? And what is your config
(card type, number of cards, type/number of lnbs, diseqc-switch, multiswitch 
etc??).

bye, reiner

Configuration:
1*DVBs 1.3 with CI-Interface
Multifeed dish with two philips single-lnbs (one with integrated diseqc
switch)




>So I looked into the driver again and saw that in the mon_tune() function 
>of
>dvb.c actions are only taken if the new settings (like 'srate', 'fec' etc.)
>differ from the old ones. That could explain why VDR's two retries almost 
>never
>worked, but tuning to a different transponder helped (sometimes).
>
>I therefore commented out the checks whether the settings have actually 
>changed,
>so that the tuning commands would always be sent to the DVB card. The 
>result was
>that still sometimes channels don't sync at the first attempt, but (as far 
>as I
>have seen in my tests) they always sync when VDR retries tuning to the same 
>channel.
>
>So, if those of you who can reproduce the problem with my ctest.c program 
>(or with
>VDR itself) could please apply the following patch to the driver and try 
>again
>with this patched version, I would appreciate learning about your results.
>What you should see that either tuning always works at the first attempt 
>(that would
>be the best case), or that it succeeds after the first retry. There should 
>never be
>more than one retry (if there is, then this is probably not the solution to 
>the
>problem).
>
>Klaus
>
>--- dvb.c.001   Fri Sep  7 08:21:43 2001
>+++ dvb.c       Sat Sep  8 11:28:02 2001
>@@ -2771,16 +2772,20 @@
>  {
>          switch (dvb->dvbtype) {
>          case DVB_S:
>+/*
>                  if (dvb->front.srate!=dvb->new_srate ||
>                      dvb->front.fec!=dvb->new_fec) {
>+*/
>                          dvb->front.srate=dvb->new_srate;
>                          dvb->front.fec=dvb->new_fec;
>                          demod_command(dvb, DVB_SET_FRONTEND, 
>&dvb->front);
>                          //if (dvb->demod_type==DVB_DEMOD_STV0299)
>                                  demod_command(dvb, DVB_RESET, 0);
>+/*
>                  }
>                  if (dvb->front.freq==dvb->new_freq && fe_lock(dvb))
>                          return mon_complete(dvb);
>+*/
>
>                  dvb->front.freq=dvb->new_freq;
>                  tuner_command(dvb, TUNER_SET_TVFREQ, &dvb->front.freq);
>
>--
>_______________________________________________________________
>
>Klaus Schmidinger                       Phone: +49-8635-6989-10
>CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
>Hofmark 2                               Email:   kls@cadsoft.de
>D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
>_______________________________________________________________
>
>
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>


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