[linux-dvb] [discussion] Frontend capable of reporting and supporting supported diseqc version

Manu Abraham abraham.manu at gmail.com
Mon Dec 11 23:04:08 CET 2006

Michel Verbraak wrote:
> I did a search through the different mailing list archives but could not
> find an answer to the following question:
> Why is the frontend/card driver (dvb-s) not capable of telling which
> version of diseqc it can support?

In most cases, the demod handles the diseqc functionality. But there are
cases where diseqc functionality depends on  hardware also (in the case
of diseqc 2x) the receiver could have been not wired at all.

> In the dvb_frontend_info struct or the enum fe_caps nothing is specified
> about the diseqc version supported. Or should I look in some other file?
> What I currently see is that the different application,
> vdr/kaffeine/mythtv, all can send diseqc commands but the user has to
> specify the hardware connected to the card. But would it not be handy if
> the driver at least could tell which version is supported by the card so
> the application can suggest to the end user which options are available?

Only with diseqc 2x you can query back, functionality of the slaves.
for Diseqc 2x handling, IIRC, FE_DISEQC_SLAVE_REPLY ioctl can be used.

But only a diseqc 2x device will allow you to see what is behind the same.

> I happy to try to spend some time to implement this for some of the
> drives or design it for the frontend model. I think it can be
> implemented with backwards compatibality so all the old stuff will keep
> on working.
> A suggestion could be the following:
> 1. Add following values to enum fe_caps:
>       FE_CAN_DISEQC_1_0 = 0x1000000
>       FE_CAN_DISEQC_1_1 = 0x2000000
>       FE_CAN_DISEQC_1_2 = 0x4000000
>       FE_CAN_DISEQC_2_0 = 0x8000000
> 2. In the different frontends set the right diseqc capability.
> Another suggestion would be to put the default diseqc capabilities like
> gotox, gotopos, storepos in the driver and out of the dvb-apps api part.
> I know this is tricky and I do not have enough experience with linux
> drivers. Or should there be a new diseqc module/driver in which the
> external hardware can be specified by options and the application can
> talk to this part to control the diseqc capable hardware like rotors and
> switches?

There are diseqc 2x switches, but haven't seen any diseqc 2x rotors.

> The reason why I ask this is because it will create a transparent way
> for applications to communicate to the diseqc capable hardware connected
> to the dvb-s card.
> I do not know if this subject or discussion has been helt before but
> please tell me if I'm wrong or when it could be a good suggestion.

There have been discussions on the subject earlier. To have a better
idea, you could go through  the archives

> Regards,
> Michel.


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