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    SubjectRe: [RFC] Should we create a raw input interface for IR's ? - Was: Re: [PATCH 1/3 v2] lirc core device driver infrastructure
    From
    On Tue, Dec 8, 2009 at 8:30 AM, Mauro Carvalho Chehab
    <mchehab@redhat.com> wrote:
    > Andy Walls wrote:
    >> On Mon, 2009-12-07 at 20:22 -0800, Dmitry Torokhov wrote:
    >>> On Mon, Dec 07, 2009 at 09:42:22PM -0500, Andy Walls wrote:
    >>
    >>>> So I'll whip up an RC-6 Mode 6A decoder for cx23885-input.c before the
    >>>> end of the month.
    >>>>
    >>>> I can setup the CX2388[58] hardware to look for both RC-5 and RC-6 with
    >>>> a common set of parameters, so I may be able to set up the decoders to
    >>>> handle decoding from two different remote types at once.  The HVR boards
    >>>> can ship with either type of remote AFAIK.
    >>>>
    >>>> I wonder if I can flip the keytables on the fly or if I have to create
    >>>> two different input devices?
    >>>>
    >>> Can you distinguish between the 2 remotes (not receivers)?
    >>
    >> Yes.  RC-6 and RC-5 are different enough to distinguish between the two.
    >> (Honestly I could pile on more protocols that have similar pulse time
    >> periods, but that's complexity for no good reason and I don't know of a
    >> vendor that bundles 3 types of remotes per TV card.)
    >
    > You'll be distinguishing the protocol, not the remote. If I understood
    > Dmitry's question, he is asking if you can distinguish between two different
    > remotes that may, for example, be using both RC-5 or both RC-6 or one RC-5
    > and another RC-6.

    RC-5 and RC-6 both contain an address field. My opinion is that
    different addresses represent different devices and in general they
    should appear on an input devices per address.

    However, I prefer a different scheme for splitting the signals apart.
    Load separate maps containing scancodes for each address. When the IR
    signals come in they are matched against the maps and a keycode is
    generated when a match is found. Now there is no need to distinguish
    between the remotes. It doesn't matter which remote generated the
    signal.

    scancode RC5/12/1 - protocol, address, command tuplet. Map this to
    KP_1 on interface 1.
    scancode RC5/7/1 - protocol, address, command tuplet. Map this to KP_1
    on interface 2.

    Using the maps to split the commands out also fixes the problem with
    Sony remotes which use multiple protocols to control a single device.
    scancode Sony12/12/1 - protocol, address, command tuplet. Map this to
    power_on on interface 1.
    scancode Sony15/12/1 - protocol, address, command tuplet. Map this to
    KP_1 on interface 1.


    >
    >>>  Like I said,
    >>> I think the preferred way is to represent every remote that can be
    >>> distinguished from each other as a separate input device.
    >>
    >> OK.  With RC-5, NEC, and RC-6 at least there is also an address or
    >> system byte or word to distingish different remotes.  However creating
    >> multiple input devices on the fly for detected remotes would be madness
    >> - especially with a decoding error in the address bits.
    >>
    >> Any one vendor usually picks one address for their bundled remote.
    >> Hauppaugue uses address 0x1e for it's RC-5 remotes AFAICT.
    >
    > The address field on RC-5 protocol is not meant to distinguish different
    > vendors, but different "applications". It identifies that a code should
    > be sent to a TV or a VCR, or a DVD or a SAT.
    >
    > In the case of bundled IR's, some vendors like Hauppauge opted to use a
    > reserved address to avoid conflicts with other equipments. It happens that
    > vendor's "reserved address" can be different between two different vendors,
    > but is just an educated guess to say that an address equal to 0x1e is Hauppauge.
    >
    > Cheers,
    > Mauro.
    > --
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    >



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    Jon Smirl
    jonsmirl@gmail.com
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