Message-ID: <4B1E61E1.5070705@redhat.com>
Date: Tue, 08 Dec 2009 12:25:37 -0200
From: Mauro Carvalho Chehab <mchehab@redhat.com>
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To: Krzysztof Halasa <khc@pm.waw.pl>
CC: Dmitry Torokhov <dmitry.torokhov@gmail.com>, Andy Walls <awalls@radix.net>,
       Jarod Wilson <jarod@wilsonet.com>,
       Christoph Bartelmus <lirc@bartelmus.de>, j@jannau.net, jarod@redhat.com,
       linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
       linux-media@vger.kernel.org, superm1@ubuntu.com
Subject: Re: [RFC] Should we create a raw input interface for IR's ? - Was:
 Re: [PATCH 1/3 v2] lirc core device driver infrastructure
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Krzysztof Halasa wrote:
> Mauro Carvalho Chehab <mchehab@redhat.com> writes:
>> IMO, the better is to have an API to allow creation of multiple interfaces
>> per IR receiver, based on some scancode matching table and/or on some
>> matching mask.
> 
> I think setting the keytables for each logical device would do.

Yes.
> 
> I.e. just have a way to create additional logical devices. Each can have
> its own keytable. The decoders would send their output to all logical
> remotes, trying to match the tables etc.
> 
>> It should be possible to use the filter API to match different IR's by
>> vendor/product on protocols that supports it,
> 
> That would mean unnecessary limiting.

If the mask is (unsigned)-1, it will not add any limit. This should be the default.

The advantage of the mask is that you can speedup the keycode decoding by not calling
a seek routine in the cases where it doesn't make sense.

Also, the cost of scancode & scancode_mask is cheap enough, comparing with the 
potential optimization gain of not seeking a data in a table that wouldn't match anyway.

Also, the IR core may automatically generate such mask, by doing an "and" operation of all
the scancodes at the table during table initialization/changes. If the mask is zero, it
defaults to use a (unsigned) -1 mask.

Cheers,
Mauro.

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