From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chase Douglas Subject: Re: Mixed "pen" and multitouch input devices Date: Thu, 15 Mar 2012 11:29:37 -0700 Message-ID: <4F623511.3040907@gmail.com> References: <20120315155235.GA6783@stud.informatik.uni-erlangen.de> <20120315175635.GA23155@stud.informatik.uni-erlangen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:58643 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873Ab2COS3N (ORCPT ); Thu, 15 Mar 2012 14:29:13 -0400 Received: by dajr28 with SMTP id r28so4878471daj.19 for ; Thu, 15 Mar 2012 11:29:13 -0700 (PDT) In-Reply-To: <20120315175635.GA23155@stud.informatik.uni-erlangen.de> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Thorsten Wissmann Cc: Chris Bagwell , Henrik Rydberg , linux-input@vger.kernel.org, =?ISO-8859-1?Q?Maximilian_Kr=FCger?= , i4passt@lists.informatik.uni-erlangen.de On 03/15/2012 10:56 AM, Thorsten Wissmann wrote: > On Thu, Mar 15, 2012 at 12:27:22PM -0500, Chris Bagwell wrote: >> Its also true that sharing ABS_X/Y events between both a BTN_TOOL_PEN >> and a BTN_TOOL_FINGER will confuse most user land apps (they think >> only touchpads can declare BTN_TOOL_FINGER's but this is a >> touchscreen) and it also has bad side affects to the kernel's MT >> pointer emulation functions. >> >> You can look at kernel drivers/input/touchscreen/wacom_w8001.c for an >> example touchscreen that supports pen and at least 2 MT touches on a >> single /dev/input device (because HW packets come over single serial >> interface). It does not declare a BTN_TOOL_FINGER nor use pointer >> emulation to overcome issues I mentioned and xf86-input-wacom >> understands how to handle this device. >> >> If you want to work with other unmodified user land apps (perhaps >> xf86-input-evdev for touches) then its probably easiest to split pen >> and touch to separate input devices. drivers/input/tablet/wacom_wac.c >> shows some examples of that approach but that driver doesn't have to >> work to hard to split in to 2 input devices because the USB device >> already puts the events on separate USB interfaces. > > OK. We want the device to work with the xf86-input-evdev driver. So we > will split it into two devices. Or you could teach evdev to know how to handle mixed devices :). I think that's the "better" approach over all, but it's up to you. -- Chase