Re: [RFC] What are the goals for the architecture of an in-kernel IR system?

Krzysztof Halasa
2009-11-28T17:21:39Z

lirc@bartelmus.de (Christoph Bartelmus) writes:

> Nobody here doubts that you can implement a working RC-5 decoder. It's
> really easy. I'll give you an example why Maxim thinks that the generic
> LIRC approach has advantages:

But surely not when compared to an in-kernel decoder _and_ the one in
lircd? :-)

> Look at the Streamzap remote (I think Jarod submitted the lirc_streamzap
> driver in his patchset):
> http://lirc.sourceforge.net/remotes/streamzap/PC_Remote
>
> This remote uses RC-5. But some of the developers must have thought that
> it may be a smart idea to use 14 bits instead the standard 13 bits for
> this remote. In LIRC you won't care, because this is configurable and
> irrecord will figure it out automatically for you. In the proposed kernel
> decoders I have seen until now, you will have to treat this case specially
> in the decoder because you expect 13 bits for RC-5, not 14.

Well, the 14-bit RC5 is de-facto standard for some time now. One of the
start bits, inverted, now functions as the MSB of the command code.
13-bit receiver implementations (at least these aimed at "foreign"
remotes) are obsolete.

> Well, it can be done. But you'll have to add another IR protocol define
> for RC-5_14, which will become very ugly with many non-standard protocol
> variations.

No, the 14-bit version is designed to be backward compatible.
--
Krzysztof Halasa