[linux-dvb] Re: DVB-CI question

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Friday 26 March 2004 19:18, Johannes Stezenbach wrote:
> On Fri, Mar 26, 2004 at 06:17:07PM +0000, Andrew de Quincey wrote:
> > However, I have some proposals for fixing the IOCTL interface, to support
> > different types of CA device properly, and removing some the cruft. I
> > suggest we then just have different device types for the
> > CA_GET_MSG/CA_SEND_MSG ioctls, which would work quite nicely with the
> > other changes I had in mind.
> >
> > Note the changes only affect the CA_GET_MSG/CA_SEND_MSG ioctls, and
> > nothing uses them right now 'cos they're a bit broken.....
>
> Could you please have a look at the dvb-kernel-v4 CI API?
> Comments on it are welcome.

Aha, that makes much more sense. Having one ca device per slot simplifies 
client-side code as well as the kernel.

The only problem I can see is that that API doesn't take into account that 
different devices operate at different levels . From what Ralph was saying, 
the Twinhan cards operate above the TPDU level.

For the stuff I was messing about with, I was thinking of something like the 
FE_SET_FRONTEND ioctl... so you had a structure like the following for the 
SEND_MSG/GET_MSG ioctls:

struct dvb_ci_msg {
	int msg_type;
	
	union {
		struct tpdu { ... };
		struct othermsgtype1 { ... };
		struct othermsgtype2 { ... };
	} u;
}

The SLOT_STATUS ioctl struct then had another field saying what type(s) of 
messages the slot supported.

You could also support the av7110-style descriptors by adding a new type/union 
member... but I don't think those matter any more from what I remember you 
saying.

Would the CI read()/write() interface be removed in v4?


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