[linux-dvb] S2API - Status - Thu Sep 11th

Steven Toth stoth at linuxtv.org
Sun Sep 14 18:47:00 CEST 2008

Steven Toth wrote:
> Johannes Stezenbach wrote:
>> On Fri, Sep 12, 2008, Steven Toth wrote:
>>> Christophe Thommeret wrote:
>>>> As far  as i understand, the cinergyT2 driver is a bit unusual, e.g. 
>>>> dvb_register_frontend is never called (hence no dtv_* log messages). 
>>>> I don't know if there is others drivers like this, but this has to 
>>>> be investigated cause rewritting all drivers for S2API could be a 
>>>> bit of work :)
>>>> P.S.
>>>> I think there is an alternate driver for cinergyT2 actually in 
>>>> developement but idon't remember where it's located neither its state.
>>> Good to know. (I also saw your followup email). I have zero 
>>> experience with the cinergyT2 but the old api should still be working 
>>> reliably. I plan to investigate this, sounds like a bug! :)
>> Holger was of the opinion that having the demux in dvb-core
>> was stupid for devices which have no hw demux, so he
>> programmed around dvb-core. His plan was to add a
>> mmap-dma-buffers kind of API to the frontend device,
>> but it never got implemented.
>> Anyway, it's bad if one driver is different than all the others.
> Hmm, I didn't realize this, good to know.
> Now it's peaked my interest, I'll have to look at the code.
> The existing API should still work at a bare minimum, if it's not - it 
> needs to.

So I looked the the cinergyT2 code, that's a complete eye-opener. It has 
it's own ioctl handler, outside of dvb-core.

It's a good news / bad news thing.

The good news is that this driver will not be effected by the S2API 
changes, so nothing can break.

The bad news is that this driver will not be effected by the S2API 
changes, so it doesn't get the benefit.

Regardless of S2API or multiproto, I see no reason why we shouldn't 
bring this driver back into dvb-core.

I don't have a device to test, but here's a patch (0% tested, with bugs 
probably) that converts the module back to a regular dvb-core compatible 
device, so the S2API would work with this. If anyone wants to test this, 
and finds bugs - I won't get back to this driver for a couple of weeks - 
so your patches would be welcome. :)

Frankly, is S2API is selected for merge and we have enough users of the 
current non-dvb-core driver, I'll probably re-write it from the spec.

So much to do, so little time.

- Steve
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