From mboxrd@z Thu Jan 1 00:00:00 1970 From: Henrik Rydberg Subject: Re: [PATCH 0/4] Alternative approach to MT_TOOL_ENVELOPE Date: Wed, 15 Dec 2010 20:36:08 +0100 Message-ID: <4D0918A8.6080207@bitmath.org> References: <4D0897F3.7040500@bitmath.org> <4D08FD74.4060403@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from csmtp2.one.com ([91.198.169.22]:35504 "EHLO csmtp2.one.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755154Ab0LOTgL (ORCPT ); Wed, 15 Dec 2010 14:36:11 -0500 In-Reply-To: <4D08FD74.4060403@canonical.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Chase Douglas Cc: Dmitry Torokhov , Chris Bagwell , Peter Hutterer , linux-input , "linux-kernel@vger.kernel.org" >>> I think that presence of pen/touch can be detected by having >>> BTN_TOOL_PEN and BTN_TOOL_FINGER. However in this case the tool is >>> finger, so I do not think we should introduce BTN_TOOL_ENVELOPE. Maybe >>> this is another case where we should employ the proposed device flags? >> >> Yes. Having something like INPUT_QUIRK_SEMI_MT might be enough, and we could >> drop the whole MT_TOOL_ENVELOPE circus. Chase, Peter, Chris, would you be >> comfortable with such a solution? > > That sounds like a good solution to me. I believe it would resolve all > the issues I had. Sounds good. > As I attempted to write up more documentation, I thought of the > following. What do you think? > > With regards to partial MT devices, if the device provides a single > valued property, such as pressure and tool type for synaptics, it may > only be provided through the traditional property semantics, i.e. > ABS_PRESSURE and BTN_TOOL_*. If the device provides multiple values for > a property, then ABS_MT_* types may be used as well to provide up to two > values, though the client should understand there's no direct > correlation between the slot's coordinates and the property. I could see > this being used to provide info on multiple tool types or a high and low > pressure. > > Enforcing the above behaviour provides even more information about the > capabilities of the device based solely on the evdev codes published. Looks good, but I do not think we need to formalize all possibilities here, only the usage of MT data for bounding rectangle and ST data for finger count. Referring to the patch just sent: whenever INPUT_PROP_SEMI_MT is true, this behavior is expected. In the event of new odd hardware, the combination of a new property quirk and a documented recipe should do the trick. Thanks, Henrik