From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Subject: Re: [PATCH 2/2] input: mt: Document the MT event slot protocol (rev3) Date: Sat, 22 May 2010 23:15:53 +0200 Message-ID: <4BF84989.3020004@euromail.se> References: <4BF6B673.1080507@euromail.se> <20100521165218.GA26439@core.coreip.homeip.net> <4BF6BB43.2020405@euromail.se> <20100521172222.GB26439@core.coreip.homeip.net> <4BF6C303.7030804@euromail.se> <20100521174140.GA23155@core.coreip.homeip.net> <4BF6C7B6.2020008@euromail.se> <4BF7A4E8.3050806@seas.upenn.edu> <4BF7B438.8000001@euromail.se> <20100522201637.GC30464@core.coreip.homeip.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ch-smtp03.sth.basefarm.net ([80.76.149.214]:40936 "EHLO ch-smtp03.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755773Ab0EVVQX (ORCPT ); Sat, 22 May 2010 17:16:23 -0400 In-Reply-To: <20100522201637.GC30464@core.coreip.homeip.net> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Dmitry Torokhov Cc: Rafi Rubin , Ping Cheng , Andrew Morton , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Mika Kuoppala , Peter Hutterer , Benjamin Tissoires , Stephane Chatty , Michael Poole Dmitry Torokhov wrote: > On Sat, May 22, 2010 at 12:38:48PM +0200, Henrik Rydberg wrote: >> Rafi Rubin wrote: >>> On 05/21/10 13:49, Henrik Rydberg wrote: >>>> Dmitry Torokhov wrote: >>>>> I guess this is where our disconnect lies as when I am looking at the >>>>> event names I view all *_MT_* events as related to the multitouch >>>>> protocol handling. >>>>> >>>> Yes. It is true that slot control is MT related, but I am looking at this from >>>> the perspective of future expansions like KEY_MT, KEY_REL, and such, finding a >>>> way to signal to user space which events are handled via slots. If we had >>>> ABS_MT_SLOT, we would most likely get applications which store ABS_MT_SLOT as an >>>> attribute of the slot together with ABS_MT_POSITION_X, ABS_MT_TOUCH_MAJOR, etc, >>>> which is just not right. So the proposal is ABS_SLOT. May we have your verdict, >>>> please. :-) >>>> >>>> Henrik >>>> >>> How many fingers can type on cap of a key? >> It depends on the size of the key, does it not. :-) >> >> Getting serious, it is anyone's guess what will happen next, but I was picturing >> a table, with a large multitouch screen and buttons along the side of the table. >> Sure, we can do "ABS_BTN_0", "ABS_BTN_1", etc, but with slots in place, it seems >> more natural to use something like "ABS_MT_BTN_X". While at it, REL_MT event >> makes sense for those touchscreen techniques which register changes, like >> acoustic pulse recognition. >> > > While I could see relative MT events I do not understand the need for > slotted key events. We already allow pressing multiple keys at once and > if a device has 2 separate keys with the same event - they either should > be treated as one logical key or 2 separate input devices. > Understood. Henrik