From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078Ab0CTT1X (ORCPT ); Sat, 20 Mar 2010 15:27:23 -0400 Received: from mail-qy0-f179.google.com ([209.85.221.179]:52449 "EHLO mail-qy0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457Ab0CTT1W convert rfc822-to-8bit (ORCPT ); Sat, 20 Mar 2010 15:27:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=aQ6Gkxu+VfKEpmf2Y8DZO1TvlFcDvVw+PPh+W3ENSRmSlzA7sf+1Ke+mvxaj6/e+IR cv2BlYCJp9f5XV0sIRWss8KSFX/gLBvKOj/QARnb7TWBEpdVY47csCH/I6LAmbDiy+Nu UsOlyylwy63wZthTrZREpuwxqHqHvQQwroyFA= MIME-Version: 1.0 In-Reply-To: <167e8a331003192151o593809bbhcda68e284185dd4a@mail.gmail.com> References: <4BA358DB.20708@enmesh.se> <167e8a331003192151o593809bbhcda68e284185dd4a@mail.gmail.com> Date: Sun, 21 Mar 2010 00:57:20 +0530 Message-ID: <5d5443651003201227w27314533w6be3cdd8fb9bf5aa@mail.gmail.com> Subject: Re: input: mt: Software finger tracking in the kernel? From: Trilok Soni To: Ping Cheng Cc: Henrik Rydberg , Dmitry Torokhov , linux-input , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ping, On Sat, Mar 20, 2010 at 10:21 AM, Ping Cheng wrote: > On Fri, Mar 19, 2010 at 3:58 AM, Henrik Rydberg wrote: >> Hi Dmitry, >> >> there is an ongoing discussion about adding multitouch to X >> (http://lists.x.org/archives/xorg-devel/2010-March/006206.html), which is >> beginning to take on more solid form. >> >> One of the suggestions emerging from that discussion is to add the software >> finger tracking to the kernel. Back in summer 2009 when I thought about this, I >> disregarded it as being too experimental. I have since then reconsidered, >> starting to think it really is the right place. >> >> The MT protocol allows applications to take advantage of multi-contact hardware, >> but leaves the problems of finger tracking and filtering to the user. Arguably, >> no application can make good use of MT without these, so the problem is pushed >> forward, in this case to evdev or equivalent. >> >> The knowledge of signal-to-noise ratios and prior input states resides in the >> kernel. Because of this, the finger matching and filtering would naturally >> reside within the kernel. >> >> So, if there were to appear patches to include matching in the input core, would >> you consider them? :-) > > I support the idea to add a tracking ID and a filter to _MT_.  I'd > also like to make the filtering method more "device driver developer" > friendly, i.e., give the developer the option to turn the filter on or > off.  If you plan to use a constant for the filtering method, please > allow the developer to choose that constant too. > > Another attribute associated with _MT_ is the pressure/capacity. > Report this value would offer more room for MT-aware application to > add new features. We have ABS_MT_PRESSURE added recently. I hope you are asking the same. -- ---Trilok Soni http://triloksoni.wordpress.com http://www.linkedin.com/in/triloksoni