[linux-dvb] Re: DVB-CI question

[Johannes Stezenbach <js@convergence.de>]

On Fri, Mar 26, 2004 at 07:41:17PM +0000, Andrew de Quincey wrote:
> 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;
> }

Makes sense. Like I said before, I don't know that much about CI,
so I removed everything from the API that I thought was useless.
(It's always easier to add stuff later than to remove something).

> 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?

Yes. No need for two differtent methods for the same thing.


Johannes


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