Re: [PATCH] input: Add a detailed multi-touch finger data report protocol

Dmitry Torokhov
2008-11-21T16:04:52Z

Hi Henrik,

On Fri, Nov 21, 2008 at 03:44:44PM +0100, Henrik Rydberg wrote:
> Dmitry,
>
> My patch is all wrong. It would certainly benefit from using the
> EV_SYN/SYN_MT_REPORT, but the defuzz mechanism of the EV_ABS class
> simply will not work when sending data for several different fingers
> using the same event.
>
> I can see two clear alternatives: either add a new event class, EV_MT,
> which sends all data without trying to limit the bandwidth, or forget
> about the whole serial-finger-data idea and expand the current EV_ABS
> class with an array of MT finger data [1]. I would very much appreciate
> your input on this. Maybe there is a third option.
>

I don't like the idea of a new class since the finger data is a part
of absolute device state (in my opinion anyway). I am not sure if we
really need to pre-allocate space for 10 fingers either. Could we just
mark certain EV_ABS events as uncacheable in the input core? It could
be implemented with one static bitmap.

--
Dmitry