multi-touch-dev team mailing list archive

[Benjamin Tissoires <tissoire@xxxxxxx>]

Hi Armando,

On 03/14/2011 01:23 PM, Duncan McGreggor wrote:
> On 03/11/2011 03:43 AM, Armando Visconti wrote:
> > All,
> >
> > I see a discussion concerning the MT protocol and Android here:
> > http://groups.google.com/group/android-platform/browse_thread/thread/fc717d35b784afb1
> >
> >
> > Still not able to understand what protocol Android is currently using
> > for multi-touch

We try to summarize this on our site: 
http://lii-enac.fr/en/architecture/linux-input/multitouch-android-howto.html

here is the quote:
-------------------
Adapt the driver for Android
Android uses a variant of the early Linux kernel multitouch protocol. 
You need to adapt your new driver.
modify the _input_mapping function so as to make sure that 
ABS_MT_TOUCH_MAJOR is published. You can for instance replace 
ABS_MT_TRACKING_ID in 'case HID_DG_CONTACTID'.
modify the _filter_event function so as to make sure that 
ABS_MT_TOUCH_MAJOR=1 is emitted when a finger first touches the panel, 
and ABS_MT_TOUCH_MAJOR=0 when it is released. The exact code depends on 
the driver.
-------------------

A cleaner way to explain (without code) is:

Android detects a multitouch device when ABS_MT_TOUCH_MAJOR and 
ABS_MT_TRACKING_ID are present. Then, you can use the protocol A
by reporting contact through ABS_MT_TOUCH_MAJOR.

> > and if it will be merged with MT Type B protocol or not.
> > I guess they should go for it.

Currently, developers told us that they won't have the time to do it for 
Honeycomb.

Cheers,
Benjamin

> > Any feedback?
> >
> > Thx,
> > Arm
>
> Hey Armando,
>
> Looks like no one has responded to you yet. As such, I've added your
> question to the agenda for discussion at the next team meeting. I'll let
> you know what comes up, if a response isn't forthcoming on the list.
>
> Thanks for your question!
>
> d
>
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