From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Huddleston Subject: Re: [PATCH] appletouch: Improved finger detection Date: Thu, 07 May 2009 23:13:26 -0700 Message-ID: <4A03CD86.4010402@freedesktop.org> References: <3AC3E247-D85C-4D8A-A73B-34677C32C2D5@freedesktop.org> <20090508025839.GC30616@dtor-d630.eng.vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from cloud.CS.Berkeley.EDU ([128.32.36.234]:53192 "EHLO mail.outersquare.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753231AbZEHGNj (ORCPT ); Fri, 8 May 2009 02:13:39 -0400 In-Reply-To: <20090508025839.GC30616@dtor-d630.eng.vmware.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: linux-input@vger.kernel.org Dmitry Torokhov wrote: > HI Jeremy, > > On Tue, May 05, 2009 at 12:10:34PM -0700, Jeremy Huddleston wrote: >> The appletouch driver is prone to reporting multiple fingers when only >> one is >> pressing. The appletouch driver queries an array of pressure sensors >> and >> counts local maxima in pressure to determine the number of fingers. It >> just >> does this on the raw values, so a data stream like: >> >> 0 100 250 300 299 300 250 100 0 >> >> actually registers as 2 fingers. >> >> This patch updates the logic to ignore small dips in pressure that are >> less >> than the threshold. >> > > Does it still detect 2 fingers as 2 fingers when they are held together? > Yes... and 3 when 3 are there. Before, it would frequently report 3 instead of 2 or 2 instead of 1. I have found the behavior with this patch very reliable... the old behavior was not reliable for me (perhaps due to a precision issue in hardware... or a dent in my finger).