From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] input: Add a detailed multi-touch finger data report protocol Date: Fri, 21 Nov 2008 11:04:36 -0500 Message-ID: <20081121110128.ZZRA012@mailhub.coreip.homeip.net> References: <49142351.9080805@euromail.se> <20081119113508.ZZRA012@mailhub.coreip.homeip.net> <4926C95C.7000609@bitmath.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4926C95C.7000609@bitmath.org> Sender: linux-kernel-owner@vger.kernel.org To: Henrik Rydberg Cc: Henrik Rydberg , Andrew Morton , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org Hi Henrik, On Fri, Nov 21, 2008 at 03:44:44PM +0100, Henrik Rydberg wrote: > Dmitry, > > My patch is all wrong. It would certainly benefit from using the > EV_SYN/SYN_MT_REPORT, but the defuzz mechanism of the EV_ABS class > simply will not work when sending data for several different fingers > using the same event. > > I can see two clear alternatives: either add a new event class, EV_MT, > which sends all data without trying to limit the bandwidth, or forget > about the whole serial-finger-data idea and expand the current EV_ABS > class with an array of MT finger data [1]. I would very much appreciate > your input on this. Maybe there is a third option. > I don't like the idea of a new class since the finger data is a part of absolute device state (in my opinion anyway). I am not sure if we really need to pre-allocate space for 10 fingers either. Could we just mark certain EV_ABS events as uncacheable in the input core? It could be implemented with one static bitmap. -- Dmitry