From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263423AbVBCWSj (ORCPT ); Thu, 3 Feb 2005 17:18:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261911AbVBCWPx (ORCPT ); Thu, 3 Feb 2005 17:15:53 -0500 Received: from av9-2-sn4.m-sp.skanova.net ([81.228.10.107]:44165 "EHLO av9-2-sn4.m-sp.skanova.net") by vger.kernel.org with ESMTP id S262754AbVBCWGb (ORCPT ); Thu, 3 Feb 2005 17:06:31 -0500 To: Giuseppe Bilotta Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] Fix "pointer jumps to corner of screen" problem on ALPS Glidepoint touchpads. References: From: Peter Osterlund Date: 03 Feb 2005 23:06:28 +0100 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Giuseppe Bilotta writes: > Peter Osterlund wrote: > > Only parse a "z == 127" packet as a relative Dualpoint stick packet if > > the touchpad actually is a Dualpoint device. The Glidepoint models > > don't have a stick, and can report z == 127 for a very wide finger. If > > such a packet is parsed as a stick packet, the mouse pointer will > > typically jump to one corner of the screen. > > I remember reading specs of a touchpad (can't remember if it > was ALPS or Synaptics) (driver) which could do "palm > detection" (basically ignoring events when a large part of the > hand accidentally touched/pressed the pad, FWICS). Some synaptics touchpads can do palm detection in firmware, but the software driver has to decide if the corresponding events shall be ignored or not. Anyway, this is unrelated to the patch. Without this patch, the packet from the touchpad will be parsed incorrectly as a very big stick motion, so a higher level driver (such as the X driver) can't really see that there might be a palm touching the pad. -- Peter Osterlund - petero2@telia.com http://web.telia.com/~u89404340