From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Poole Subject: Re: [PATCH] input: mt: introduce MT event slots Date: Wed, 07 Apr 2010 23:07:09 -0400 Message-ID: <87tyrmiqw2.fsf@troilus.org> References: <1270685590-2204-1-git-send-email-rydberg@euromail.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from na3sys009aog107.obsmtp.com ([74.125.149.197]:42849 "HELO na3sys009aog107.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753145Ab0DHDHP (ORCPT ); Wed, 7 Apr 2010 23:07:15 -0400 In-Reply-To: <1270685590-2204-1-git-send-email-rydberg@euromail.se> (Henrik Rydberg's message of "Thu, 8 Apr 2010 02:13:10 +0200") Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Henrik Rydberg Cc: Dmitry Torokhov , Andrew Morton , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Henrik Rydberg writes: > With the rapidly increasing number of intelligent multi-contact and > multi-user devices, the need to send digested, filtered information > from a set of different sources within the same device is imminent. > This patch adds the concept of slots to the MT protocol. The slots > enumerate a set of identified sources, such that all MT events > can be passed independently and selectively per identified source. > > The protocol works like this: Instead of sending a SYN_MT_REPORT > event immediately after the contact data, one sends a SYN_MT_SLOT > event immediately before the contact data. The input core will only > emit events for the slots corresponding to the contacts that have > changed. It is assumed that the same slot is used for the duration > of an initiated contact. How would the slot number for a contact be chosen? If the kernel makes that assignment, what should a "slot" correspond to from a computer user's perspective? "Set[s] of identified sources" is a little vague: Does it mean contacts from one hand, contacts in one displayed window (assuming the touch surface is a screen), or something else? (I assume it would not duplicate the blob or tracking IDs already defined for MT events.) It seems like those would be important aspects of the protocol to document in Documentation/input/multi-touch-protocol.txt -- otherwise, driver implementers or application developers might get it wrong. Michael Poole