[linux-dvb] [PATCH] Multi protocol support (stage #1)

Alan Nisota alannisota at gmail.com
Tue Jun 13 17:01:50 CEST 2006


On 6/12/06, Johannes Stezenbach wrote:
>On Sun, Jun 11, 2006, Alan Nisota wrote:
>> Well, as it didn't seem that S2 was going anywhere, I had lost track
>> of this conversation a month or so ago, but now that I had to do some
>> mythtv work, I am trying to catch up.  I've looked over Manu's patch,
>> and associated sample app, and I don't think I really understand how
>> this method is supposed to work.
While I was looking at the ver7 patch when I wrote that mail, I have
since looked at the rev7a version as well, and I dhave questions.  I
understand how to use the new API, but am unsure what is expected from
an application perspective.
Specifically, if the API is version 3.2, does that mean that all cards
can be accessed with the new DVBFE ioctls (which would make things
relatively nice, as an app needs to support only one or the other as
defined at compile-time), or does each driver need to be ported to use
the new API, in which case there needs to be some way to designate
which cards support the new drivers?

On 6/12/06, Manu Abraham  wrote:
> Johannes Stezenbach wrote:
> > My understanding is that dish network and thus the genpix
> > card have nothing to do with DVB-S2, but are just a
> > proprietary extension which adds 8PSK modulation to DVB-S.
> >
> >
>
> Yes, you are right i think.
>
> As i heard most Dish network people have this device. All it depends is
> on 8PSK modulation, looking at the the Broadcom specs
> (http://www.broadcom.com/collateral/pb/4500-PB06-R.pdf) It doesn't say
> anywhere that it is a DVB-S2 supported device, in fact, but just says
> that it supports DVB/DIRECTV/Digicipher II and that it supports
> BPSK/QPSK/8PSK/16QAM modulations. The many parts of the DVB-S2
> demodulator seem to be missing out in that Block Diagram, for example
> the PL descrambling etc which DVB-S2 makes use of.
All this is correct (I don't think we ever got the DSS stuff working
with the board yet, though when we do, it'll make things much more
interesting).  However, the need for modulation means that the board
cannot be treated as a DVB-S board, and so I plan to implement it as a
(mostly incapable) DVB-S2 board so that we don't need customized
software to support it.  So my desire is simply that an API is defined
such that I have something to implement against.

Thanks again, it appears things are closer to resolved than it first appeared.
Alan



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