← Back to team overview

multi-touch-dev team mailing list archive

Re: MT Type B events and Android


On 03/16/2011 04:41 AM, Benjamin Tissoires wrote:
> 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
> 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

Great info, Benjamin -- thanks so much!


Follow ups