[linux-dvb] twinhan 1025 - problems locking onto signal

Simon Kenyon simon at koala.ie
Mon Aug 13 18:15:16 CEST 2007


Manu Abraham wrote:
> On 8/13/07, Simon Kenyon <simon at koala.ie> wrote:
>   
>> Manu Abraham wrote:
>>     
>>> On 8/13/07, Simon Kenyon <simon at koala.ie> wrote:
>>>
>>>       
>>>> Simon Kenyon wrote:
>>>>
>>>>         
>>>>> just bought 3 cards for my mythtv master backend. silly me.
>>>>>
>>>>> anyway, using szap i find that tuning to a particular channel is at best
>>>>> a hit and miss affair.
>>>>> i have a 4x16 multiswitch which feeds astra28.2E into these three cards
>>>>> and 4 satellite receivers.
>>>>> they all get decent signal. i previously had a nexus-s and a technotrend
>>>>> 1500ci in the box and they had no problems with the signal.
>>>>>
>>>>> is there anything i can do - other than binning them?
>>>>> i'm using the hg tree of v4l-dvb.
>>>>> is there an expermental tree out there with some improvements for this card?
>>>>>
>>>>>
>>>>>           
>>>> a data point is that it will not lock onto any signals with a vertical
>>>> polarization
>>>> but will lock on to signals with a horizontal polarization (at the
>>>> second attempt - not the first).
>>>> the latter sounds like a timing issue.
>>>>
>>>>         
>>> Some of the 1025 cards have been very nasty. It resembles an older
>>> case where one card would not tune to either vertical (or was it
>>> Horizontal) completely stuck at one volytage level.
>>>
>>> To take a bite at it, load the dst module with verbose=5, module
>>> parameter. look at the logs, if you have timing errors you will see
>>> them in the log.
>>>
>>>
>>>
>>>       
>>>> i have 5 other receivers and 2 dvb-s cards which have no problems with
>>>> the signal coming from the multiswitch to which they are all attached.
>>>>
>>>> any help or even ideas of what to do to diagnose the problem out there?
>>>>
>>>>         
>>> just post the logs, will take in a look whether anything's possible.
>>>
>>>
>>>       
>> here is a log from the machine.
>> i performed 3 szaps
>> the first is to a station which did not lock (V)
>> the second two did (H)
>>
>> i hope this is enough to diagnose the problem.
>>
>>     
>
> First get the sources from linuxtv.org, follow the build procedures,
> install the drivers
>
> after that look here:
>  http://linuxtv.org/hg/v4l-dvb/file/278ff24d5531/linux/drivers/media/dvb/bt8xx/dst.c
>
>      1337 	return dst_command(state, paket, 8);
>      1338 }
>
> change it to:
>
> err = dst_command(state, paket, 8);
> msleep(200);
> return err;
>
> Also at the bginning of the function declare err as int.
>
>
> Also:
>
> move to the same path in your sources: after line #1646
>      1645 		}
>      1646 		retval = dst_write_tuna(fe);
>
>
> add a msleep(200);
>
> do a recompile, reload modules and see whether it helps
>
>   
here is the log after making the changes.
i did the same three szaps in the same order.
what is slightly different is that i reloaded the modules as part of the 
reboot sequence.
diffing the two shows slightly difference reponses to the szaps - but i 
really don't know what i'm looking for

so vertical still fails.

i do appreciate this help.
--
simon
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