From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Subject: Re: [PATCH] input: Add a detailed multi-touch finger data report protocol Date: Tue, 11 Nov 2008 12:19:26 +0100 Message-ID: <49196A3E.3050201@euromail.se> References: <49142351.9080805@euromail.se> <20081111042009.GC6776@dingo.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ch-smtp02.sth.basefarm.net ([80.76.149.213]:43699 "EHLO ch-smtp02.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754767AbYKKLTl (ORCPT ); Tue, 11 Nov 2008 06:19:41 -0500 In-Reply-To: <20081111042009.GC6776@dingo.redhat.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Peter Hutterer Cc: Dmitry Torokhov , Andrew Morton , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Peter Hutterer wrote: [...] > is there hardware that can do finger identification? (i.e. thumb vs. index > finger)? Should we accommodate for this? I believe we should start with events that fit the general idea of detailed finger information, and which can be produced by at least one existing kernel driver, so that we can test it immediately. I believe the proposed set pretty much covers it. I would love to be wrong. :-) Regarding identification, one of the harder problems involved in making use of finger data is that of matching an anonymous finger at a certain position to an identified finger, tagged with a number. This is very important in order to know if the fingers moved, which finger did the tapping, how much rotation was made, etc. Generally, this is the (euclidian) bipartite matching problem, and is one of the major computations a multi-touch X driver needs to perform. I can imagine such identification features eventually ending up on a chip. Maybe someone more knowledgeable in hardware can give us a hint.