From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Subject: Re: [PATCH 1/4] Adding documention Date: Fri, 27 Aug 2010 14:06:29 +0200 Message-ID: <4C77AA45.4030805@euromail.se> References: <1282798497-19791-1-git-send-email-rafi@seas.upenn.edu> <1282798497-19791-2-git-send-email-rafi@seas.upenn.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ch-smtp01.sth.basefarm.net ([80.76.149.212]:43580 "EHLO ch-smtp01.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751617Ab0H0MHD (ORCPT ); Fri, 27 Aug 2010 08:07:03 -0400 In-Reply-To: <1282798497-19791-2-git-send-email-rafi@seas.upenn.edu> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Rafi Rubin Cc: jkosina@suse.cz, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, dmitry.torokhov@gmail.com, chatty@enac.fr, micki@n-trig.com On 08/26/2010 06:54 AM, Rafi Rubin wrote: [...] > +Parameters > +---------- > + > +Note: values set at load time are global and will apply to all applicable > +devices. Adjusting parameters with sysfs will override the load time values, > +but only for that one device. > + > +The following parameters are used to configure filters to reduce noise: > + > +activate_slack number of fingers to ignore before processing events > + > +activation_height size threshold to activate immediately > +activation_width > + > +min_height size threshold bellow which fingers are ignored > +min_width both to decide activation and during activity > + > +deactivate_slack the number of "no contact" frames to ignore before > + propagating the end of activity events > + > +When the last finger is removed from the device, it sends a number of empty > +frames. By holding off on deactivation for a few frames we can tolerate false > +erroneous disconnects, where the sensor may mistakenly not detect a finger that > +is still present. Thus deactivate_slack addresses problems where a users might > +see breaks in lines during drawing, or drop an object during a long drag. Without contact tracking, it is hard to imagine activation filtering to work properly. I would advocate to remove this functionality from the driver, and add it in userspace instead. Henrik