Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759121AbZKYRSl (ORCPT ); Wed, 25 Nov 2009 12:18:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934820AbZKYRSi (ORCPT ); Wed, 25 Nov 2009 12:18:38 -0500 Received: from khc.piap.pl ([195.187.100.11]:34672 "EHLO khc.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933761AbZKYRSe (ORCPT ); Wed, 25 Nov 2009 12:18:34 -0500 From: Krzysztof Halasa To: Trent Piepho Cc: Maxim Levitsky , Jarod Wilson , Dmitry Torokhov , Mauro Carvalho Chehab , Jarod Wilson , linux-kernel@vger.kernel.org, Mario Limonciello , linux-input@vger.kernel.org, linux-media@vger.kernel.org, Janne Grunau , Christoph Bartelmus Subject: Re: IR raw input is not sutable for input system References: <200910200956.33391.jarod@redhat.com> <200910200958.50574.jarod@redhat.com> <4B0A765F.7010204@redhat.com> <4B0A81BF.4090203@redhat.com> <20091123173726.GE17813@core.coreip.homeip.net> <4B0B6321.3050001@wilsonet.com> <1259105571.28219.20.camel@maxim-laptop> Date: Wed, 25 Nov 2009 18:18:38 +0100 In-Reply-To: (Trent Piepho's message of "Tue, 24 Nov 2009 19:32:42 -0800 (PST)") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1524 Lines: 32 Trent Piepho writes: > The signal recevied by the ir receiver contains glitches. Depending on the > receiver there can be quite a few. It is also not trivial to turn the raw > signal sent by the remote into a digital value, even if you know what to > expect. It takes digital signal processing techniques to turn the messy > sequence of inaccurate mark and space lengths into a best guess at what > digital code the remote sent. This is of course true. Except that most receivers do that in hardware, the receiver/demodular chip such as TSOP1838 does it. If you receive with a phototransistor or a photodiode feeding some sort of ADC device (not a very smart design), sure - you have to do this yourself. I have never heard of such receiver, though. > One thing that could be done, unless it has changed much since I wrote it > 10+ years ago, is to take the mark/space protocol the ir device uses and sent > that data to lircd via the input layer. It would be less efficient, but > would avoid another kernel interface. Of course the input layer to lircd > interface would be somewhat different than other input devices, so > it's not entirely correct to say another interface is avoided. IOW, it would be worse, wouldn't it? -- Krzysztof Halasa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/