Date:	Mon, 7 Dec 2009 13:19:12 -0500
From:	Jarod Wilson <jarod@...sonet.com>
To:	Andy Walls <awalls@...ix.net>
Cc:	Mauro Carvalho Chehab <mchehab@...hat.com>,
	Krzysztof Halasa <khc@...waw.pl>,
	Christoph Bartelmus <lirc@...telmus.de>,
	dmitry.torokhov@...il.com, j@...nau.net, jarod@...hat.com,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, superm1@...ntu.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

On Nov 26, 2009, at 2:43 PM, Andy Walls wrote:

> On Thu, 2009-11-26 at 12:05 -0200, Mauro Carvalho Chehab wrote:
>> Krzysztof Halasa wrote:
>>> Andy Walls <awalls@...ix.net> writes:
>>> 
>>>> I would also note that RC-6 Mode 6A, used by most MCE remotes, was
>>>> developed by Philips, but Microsoft has some sort of licensing interest
>>>> in it and it is almost surely encumbered somwhow:
>>> 
>>> I don't know about legal problems in some countries but from the
>>> technical POV handling the protocol in the kernel is more efficient
>>> or (/and) simpler.
>> 
>> A software licensing from Microsoft won't apply to Linux kernel, so I'm
>> assuming that you're referring to some patent that they could be filled
>> about RC6 mode 6A.
>> 
>> I don't know if is there any US patent pending about it (AFAIK, only US
>> accepts software patents), but there are some prior-art for IR key
>> decoding. So, I don't see what "innovation" RC6 would be adding. 
>> If it is some new way to transmit waves, the patent issues
>> aren't related to software, and the device manufacturer had already handled
>> it when they made their devices.
>> 
>> If it is just a new keytable, this issue 
>> could be easily solved by loading the keytable via userspace.
>> 
>> Also, assuming that you can use the driver only with a hardware that comes
>> with a licensed software, the user has already the license for using it.
>> 
>> Do you have any details on what patents they are claiming?
> 
> The US Philips RC-6 patent is US Patent 5,877,702
> 
> http://www.google.com/patents?vid=USPAT5877702
> 
> Click on download PDF to get a copy of the whole patent.
> 
> I am not a lawyer.  Philips claims' all appear to tie to a transmitter
> or receiver as part of a system, but most of the claims are about
> information and bit positions and lengths.
...
> IMO, given
> 
> a. the dearth of public information about RC-6, indicating someone
> thinks it's their trade secret or intellectual property
> 
> b. Microsoft claiming to license something related to the MCE remote
> protocols (which are obviously RC-6 Mode 6A),
> 
> c. my inability to draw a "clear, bright line" that RC-6 Mode 6A
> encoding and decoding, as needed by MCE remotes, implemented in software
> doesn't violate anyone's government granted rights to exclusivity.
> 
> I think it's much better to implement software RC-6 Mode 6A encoding and
> decoding in user space, doing only the minimum needed to get the
> hardware setup and going in the kernel.  
> 
> Encoding/decoding of RC-6 by microcontrollers with firmware doesn't
> worry me. 
> 
> 
> Maybe I'm being too conservative here, but I have a personal interest in
> keeping Linux free and unencumbered even in the US which, I cannot deny,
> has a patent system that is screwed up.

So I had one of the people who does all the license and patent audits for Fedora packages look at the Philips patent on RC-6. He's 100% positive that the patent *only* covers hardware, there should be no problem whatsoever writing a software decoder for RC-6.

-- 
Jarod Wilson
jarod@...sonet.com



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