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

Michel Verbraak michel at verbraak.org
Tue Dec 12 14:17:57 CET 2006

> Hello Michel,
> Michel Verbraak wrote:
>> Manu,
>> As Joep also posts I'm not talking about can it receive diseqc 2.0
>> replies. But why can the driver not tell what version of diseqc the card
>> does support.
> The difference that i understand as related to a frontend is in the need
> to identify whether it supports Diseqc 2x or 1x. Obi wrote the same on
> the list.
> In this case , as i wrote earlier on the list, you can check whether the
> device supports 2x by seeing what the ioctl returns.
>> I took me some time, through the suppliers websites, to find out if a
>> dvb-s card was capable of supporting diseqc and which version. Twinhan
>> does specify it on its website but there are plenty which do not. The
>> TechnoTrend crads only support diseqc 1.0 and not higher.
> Which frontend is this based on ? the STV0299 ? Or do you mean the
> AV7110 based cards ? Or do you mean to say that they supported only the
> 22k tone ?
If you look on the technotrend webshop site for their TT-premium® S-2300
it says:

Steuerung LNB / (DiSEqC-) Switch (14/18V, 22KHz / DiSEqC1.0)
As wel for their other dvb-s cards.

On the KNC one website their specs do not even mention diseqc level

A friend of mine has a hauppauge Nexus-s where only in the pfd manual it
was described only capable of diseqc 1.0 (on the box was nothing
mentioned). This card is maybe from before the diseqc 1.2/2.x specs.

> What happened with Twinhan was that earlier they had the dst based (a 16
> bit x86 style microcontroller on the CI based cards and a 8 bit MCS51
> style microcontroller on the FTA cards) DVB cards. These cards did not
> expose the frontends as it is, like other cards. In this case, the
> Diseqc commands what you can send is limited on them. On the oldest
> cards there wasn't any diseqc support also, IIRC. (they did not have a
> PCI subsystem ID also, no EEPROM) Later, they added support for the PCI
> subsystem ID and 22k tone, in a later model, it would support only 3 and
> 4 byte long commands only , in another 3, 4 and 5. This were all
> dependant on the assembly code running on the microcontroller.
> For example, the same card with a STV0299 based frontend on 2 different
> models would support different functionality, depending upon the
> software running on the host microcontroller on these cards.
> So they advertised different diseqc versions as they changed things,
> eventhough the hardware remained completely the same. (The last touted
> by them was diseqc 1.2, for rotor control)
> What i remember is that some of the older Twinhan (dst based) cards, did
> not support 5 bytes and or some others. If you look at dst.c , in
> dst_tlist, you will see what i mean.
> So with the newer cards eventhough without the dst, they still advertise
> the same.
> Manu

If I look trough the different frontend sources for their
diseqc_send_master_cmd I can see the following:

The stv0299 does return an error depending if it was not able to write the
diseqc command byte or had a timeout writing. As far as I can see the
problem of the error does not tell if the diseqc command bytes were not
The cx24110 always return 0 only when the amount of diseqc command bytes <
3 or > 6 then return -EINVAL
The MT312 does the same as the stv0299.
The mb86a16 does handle errors but blames them all on "I2C transfer error".

The others i did not check but error value returned tells something about
the transfer of the diseqc command bytes to the card and not if the card
can support them.

As I understand from you it will be a big problem to get this into the
driver because the same hardware with different firmware/microcontroller
software supports different diseqc levels.

I started this thread just to see if the driver model could be adjusted so
the applications written to use the drivers can handle errors or not
supported diseqc commands better. Currently they only get an error back
which could be due to the card not supporting the diseqc command or
probably even more that the driver could not communicate to the card
because of a hw failure or a broken card.



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