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Re: MT Type B events and Android


Hi Armando,

On 03/14/2011 01:23 PM, Duncan McGreggor wrote:
On 03/11/2011 03:43 AM, Armando Visconti wrote:

I see a discussion concerning the MT protocol and Android here:

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.


Any feedback?


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!


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