[linux-dvb] DVB-S2 / Multiproto and future modulation support

Steven Toth stoth at linuxtv.org
Wed Sep 10 20:39:33 CEST 2008


Janne Grunau wrote:
> On Wednesday 10 September 2008 17:10:19 Christophe Thommeret wrote:
>> Le Wednesday 10 September 2008 15:38:23 Steven Toth, vous avez écrit :
>>>> Is this card able to deliver both S and T at the same time?
>>> No, the hardware can do S/S2 or T.
>>>
>>> The driver in the S2API tree only has S/S2 enabled (for the time
>>> being).
>> So, maybe we have to think a bit about how to add support for this
>> kind of device.
>>
>> Maybe a solution could be to have :
>> - adapter0/frontend0 -> S/S2 tuner
>> - adapter0/frontend1 -> T tuner
>>
>> So applications could know that these 2 frontends are exclusive.
>> That would not require any API change, but would have to be a rule
>> followed by all drivers.
> 
> The experimental HVR4000 does this already and we have at least initial 
> support for that in mythtv.

Yes, I believe it was added sometime ago.

> 
> I don't think this was the intended use of multiple frontends in the DVB 
> API but AFAIK all dual tuners drivers uses multiple adapters.

It actually was intended for use, it came from patches based on 
linuxtv.org/hg/~stoth/hvr3000 2 years ago, for this exact reason.

The idea died on the vine, except for a few die-hard people to 
maintained their own spin-off/derivative.

> 
> I like this approach.

So do I, it solves a lot of problems with multiple frontends on a single 
transport bus. At the time I did not patch the 7134 framework with the 
minor changes for it to comply, but if that's done then the 6-in-1 7134 
Dual DVB-S/T/Analog card would also benefit greatly. Right now that card 
only supports some functions in the kernel (IIRC).

It's been a very long time but this was also mentioned on the mailing list.

- Steve




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