Re: [PATCH 0/2] Support Physical Layer Scrambling

[Mauro Carvalho Chehab <mchehab@kernel.org>]

Em Sun, 17 Dec 2017 14:50:37 +0100
Ralph Metzler <rjkm@metzlerbros.de> escreveu:

> Athanasios Oikonomou writes:
>  > A new property DTV_SCRAMBLING_SEQUENCE_INDEX introduced to control
>  > the gold sequence that several demods support.
>  > 
>  > Also the DVB API was increased in order userspace to be aware of the
>  > changes.
>  > 
>  > The stv090x driver was changed to make use of the new property.
>  > 
>  > Those commits based on discussion previously made on the mailling list.
>  > https://www.mail-archive.com/linux-media@vger.kernel.org/msg122600.html
>  > 
>  > I would like to thanks Ralph Metzler (rjkm@metzlerbros.de) for the
>  > great help and ideas he provide me in order create those patches.
>  > 
>  > Athanasios Oikonomou (2):
>  >   media: dvb_frontend: add physical layer scrambling support
>  >   media: stv090x: add physical layer scrambling support
>  > 
>  >  .../media/uapi/dvb/fe_property_parameters.rst          | 18 ++++++++++++++++++
>  >  .../uapi/dvb/frontend-property-satellite-systems.rst   |  2 ++
>  >  drivers/media/dvb-core/dvb_frontend.c                  | 12 ++++++++++++
>  >  drivers/media/dvb-core/dvb_frontend.h                  |  5 +++++
>  >  drivers/media/dvb-frontends/stv090x.c                  | 16 ++++++++++++++++
>  >  include/uapi/linux/dvb/frontend.h                      |  5 ++++-
>  >  include/uapi/linux/dvb/version.h                       |  2 +-
>  >  7 files changed, 58 insertions(+), 2 deletions(-)
>  > 
>  > -- 
>  > 2.1.4  
> 
> Acked-by: Ralph Metzler <rjkm@metzlerbros.de>

I'm applying both patches.

> We had some thoughts about having a:
> 
> #define NO_SCRAMBLING_CODE     (~0U)
> 
> But DVB-S2 is always scrambling (with default index 0) and other delivery systems can ignore this
> property. Or do you think it is needed?
> 
> 
> One could add a define for AUTO or AUTO_S2X for the standard 7 indices to be tested
> in DVB-S2X. But either dvb_frontend.c or the demod driver would have to support this in software.
> I don't think there is a demod which supports this in hardware yet?

I think that, once we have a hardware capable of auto-detecting the gold
sequence, then a NO_SCRAMBLING_CODE (or AUTO_GOLD_SEQUENCE) could make
sense.

For now, I don't think any demod currently supports it.

Thanks,
Mauro