From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rafi Rubin Subject: Re: [PATCH] hid-ntrig.c Multitouch cleanup and fix Date: Tue, 09 Mar 2010 18:38:22 -0500 Message-ID: <4B96DBEE.4060605@seas.upenn.edu> References: <4B75E14A.2050602@seas.upenn.edu> <1266027185-5311-1-git-send-email-rafi@seas.upenn.edu> <4B760D60.6020907@seas.upenn.edu> <4B96B740.7020208@euromail.se> <4B96BAF1.5070209@seas.upenn.edu> <4B96C4A8.3060005@euromail.se> <4B96CB41.9040804@seas.upenn.edu> <4B96D85A.4060604@euromail.se> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from LION.seas.upenn.edu ([158.130.12.194]:47610 "EHLO lion.seas.upenn.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751565Ab0CIXi3 (ORCPT ); Tue, 9 Mar 2010 18:38:29 -0500 In-Reply-To: <4B96D85A.4060604@euromail.se> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Henrik Rydberg Cc: Jiri Kosina , linux-input@vger.kernel.org, dmitry.torokhov@gmail.com, chatty@enac.fr On 03/09/2010 06:23 PM, Henrik Rydberg wrote: > Rafi Rubin wrote: >>> Single touch should be goverened by one of BTN_TOUCH or ABS_PRESSURE. >>> BTN_TOOL_DOUBLETAP is a two-finger event. >> >> That definitely makes sense to me. I really don't know why wacom uses >> double tap there. >> >> Is there any harm in letting through the BTN_0 events? Is the "rdesc" >> mapping defined by the hardware or hid? > > I cannot imagine BTN_0 will do any harm. In synaptics, the BTN_X buttons are > mapped to multibuttons without clear-cut usage. The button events that carry > well-defined semantic meaning with regard to touch screens are BTN_TOUCH (any > finger), BTN_TOOL_FINGER (one finger), BTN_TOOL_PEN (pen), BTN_TOOL_DOUBLETAP > (two fingers) and BTN_TOOL_TRIPLETAP (three fingers or more). > > Henrik > Perhaps we should have a general touch device document. I looked at the evdev code. And as you say for single touch devices, BTN_TOUCH is the bit that matters. It only broken because I pulled the TOUCH <- 0 when I removed BTN_0. So why does evdev associate BTN_TOOL_FINGER with touchpads (resulting in the wrong set of assumptions and a poorly calibrated touch screen)? I suppose that's really a discussion for another list. For what its worth, onions are tasty. Rafi