[linux-dvb] Lost lock problems over extended periods of time

Manu Abraham manu at kromtek.com
Tue Jun 7 19:24:50 CEST 2005


Andrew de Quincey wrote:
> On Tuesday 07 June 2005 17:32, Andrew de Quincey wrote:
>>>>>The periods used to vary, don't know what exactly caused them to vary
>>>>>either. The variations used to happen something like what you said 10 ~
>>>>>12 hours or sometime it was 48 hours. But 72 hours seemed the maximum
>>>>>that it would go many times.
>>>>Interesting - thats exactly it.. so its across completely different
>>>>card architectures!? (I assume you're still talking about the twinhan
>>>>cards here)
>>>Exactly.. I am talking about different firmware based ones too FTA and
>>>CI based.. different generations too.. Regarding that issue i' am almost
>>>tied up in knots... :-(
>>>
>>>I had a revision AV7110 1.3 card, which was blown when i received itself
>>>from Galaxis as a sample given to one of our guys. Even an lspci did not
>>>show anything at all, on some motherboards inserting the card into the
>>>PCI slot itself would result in a hung BIOS. After that i decided that,
>>>i would never again go with one of those FF cards. (eventhough they are
>>>the same TT-PCI cards remarketed)
>>>
>>>That was the time i first started up with DVB, and in this region could
>>>not see any other hardware other than Twinhan and got my first card as
>>>well as suggested for many others as well as my company too. But the
>>>biggest problem their was drivers, whether be it Windows or Linux. well
>>>you know the rest..
>>OK, my hack doesn't help. I used the following patch in dvb_frontend.c:
>>Index: dvb_frontend.c
>>===================================================================
>>RCS
>>file:
>>/cvs/linuxtv/dvb-kernel/linux/drivers/media/dvb/dvb-core/dvb_frontend.c,v
>>retrieving revision 1.96
>>diff -a -u -r1.96 dvb_frontend.c
>>--- dvb_frontend.c      17 Nov 2004 14:30:33 -0000      1.96
>>+++ dvb_frontend.c      7 Jun 2005 16:29:35 -0000
>>@@ -507,9 +507,10 @@
>>                        else {
>>                                /* if we _WERE_ tuned, but now don't have a
>>lock,
>>                                 * need to zigzag */
>>-                               fe->state = FESTATE_ZIGZAG_FAST;
>>-                               fe->started_auto_step = fe->auto_step;
>>-                               check_wrapped = 0;
>>+                               fe->state = FESTATE_RETUNE;
>>+                               dvb_frontend_init (fe);
>>+                               printk("DVB: LOST LOCK - attempting
>>retune\n");
>>+                          continue;
>>                        }
>>                }
>>
>>But, it just sits there printing "DVB LOST LOCK". Of course when I retune
>>it works perfectly! This time, it only took about 30 mins to lose the lock
>>though.
> 
> Just a thought - could it be the DiSEQC? I'm just using simple tone/voltage 
> control myself. Do all these cards use the same LNB chip on them? The DVB-S 
> stv0299 ones I have here all seem to use an LNBP16A chip.
> 
> 

Twinhan has a STV0299 based tuner on quite a few of the cards.. but no 
LNBP16..

I don't think it is the DiSEqC, since the DiSEqC never worked properly 
on the Twinhan until recently.. But when it started working some other 
problems also came up..

What i was wondering (a wild thought) was that, is something disturbing 
the frontend settings once it is set up ? That was the only way that a 
lock could be lost on the Twinhan cards, since i cannot logically think 
of any other reason that's what written to a register is lost. But 
that's too wild a thought.

Dominique had a similar problem, but that was triggered off at a certain 
period of time nearing midnight on TPS, but could be something else 
too... Maybe he can test the same on the Twinhan DST-CI and see what's 
the effect..

Manu




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