linux-kernel - Re: [PATCH 3/3] input: mt: Move tracking and pointer emulation to input-mt (rev2)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <AANLkTingU7pUSwt6myUYzDhMVWg7PqfFpftw_hjsE4iK@mail.gmail.com>
Date:	Mon, 6 Dec 2010 13:52:12 -0600
From:	Chris Bagwell <chris@...bagwell.com>
To:	Chase Douglas <chase.douglas@...onical.com>
Cc:	Henrik Rydberg <rydberg@...omail.se>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Jiri Kosina <jkosina@...e.cz>, Ping Cheng <pingc@...om.com>,
	Peter Hutterer <peter.hutterer@...-t.net>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] input: mt: Move tracking and pointer emulation to
 input-mt (rev2)

On Mon, Dec 6, 2010 at 12:40 PM, Chase Douglas
<chase.douglas@...onical.com> wrote:
> On 12/01/2010 09:21 AM, Henrik Rydberg wrote:
>> The drivers using the type B protocol all report tracking information
>> the same way. The contact id is semantically equivalent to
>> ABS_MT_SLOT, and the handling of ABS_MT_TRACKING_ID only complicates
>> the driver. The situation can be improved upon by providing a common
>> pointer emulation code, thereby removing the need for the tracking id
>> in the driver.  This patch moves all tracking event handling over to
>> the input core, simplifying both the existing drivers and the ones
>> currently in preparation.
>
> When two or more fingers are down, one of the fingers controls
> ABS_{X,Y}. I think the aim is to emulate current behavior for
> synaptics-style touchpads, which average the position in firmware. Thus,
> we should be averaging the touch positions to generate the ABS_{X,Y} values.
>

At least for modern synaptics hardware, it does track to first touch
like this patch does.

It is maybe a weighted average were its 90% first finger and 10%
second finger.  Just moving second finger gives slight movement.

I can't really speak for other touchpad behavior.

Chris
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/