From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Subject: Re: [PATCH 7/7] elantech: average the two coordinates when 2 fingers Date: Sun, 01 Aug 2010 09:52:57 +0200 Message-ID: <4C5527D9.4080903@euromail.se> References: <4C1FD2B0.1080504@tudelft.nl> <4C1FD454.4050807@tudelft.nl> <20100721033655.GA9070@core.coreip.homeip.net> <4C532009.4020103@tudelft.nl> <4C533DC3.9070001@euromail.se> <4C53471A.9080001@tudelft.nl> <4C53ECB4.2080700@euromail.se> <20100731093312.GA3461@core.coreip.homeip.net> <4C541BC3.9000100@euromail.se> <4C54AAFF.7000206@tudelft.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from ch-smtp02.sth.basefarm.net ([80.76.149.213]:54204 "EHLO ch-smtp02.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752125Ab0HAHxU (ORCPT ); Sun, 1 Aug 2010 03:53:20 -0400 In-Reply-To: <4C54AAFF.7000206@tudelft.nl> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: =?ISO-8859-1?Q?=C9ric_Piel?= Cc: Dmitry Torokhov , "linux-input@vger.kernel.org" , Florian Ragwitz On 08/01/2010 01:00 AM, =C9ric Piel wrote: > Op 31-07-10 14:49, Henrik Rydberg schreef: >> On 07/31/2010 11:33 AM, Dmitry Torokhov wrote: >> [...] >> >>>> This sounds like a misunderstanding. To rephrase: the suggestion i= s to always >>>> send the last known one-finger touch point, and to update that poi= nt only when >>>> there is a single finger on the pad. >>>> >>> >>> This would break two-finger scrolling mode of synaptics X driver. >> >> >> I envision synaptics being MT-aware at some point, but alright, the = idea is too >> radical at this stage. >> >> Back to the original problem. When adding the second finger, the fir= st finger >> will actually be in one of the four corners of the detected rectangl= e, correct? >> So how about keeping as a state what corner of the rectangle represe= nts the >> original touch, and continue to report that corner as ABS_X/Y during= a >> two-finger touch? > That could work, but in general the policy is to not do finger tracki= ng > in the kernel. And still, if you leave this first finger before the > second finger, you'll necessarily see this "jump" as well. The difference being that all positions reported correspond to real fin= gers. The problem with this particular device is that it is more primitive th= an type A, so some method to produce correct MT information would be desirable.= Keeping track of what corners of the rectangle correspond to fingers does not t= ell which finger is which (thus not finger tracking), but makes this device compl= y with type A, which is capable of detecting an unordered set of actual touch = points. Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-input" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html