Re: [PATCH 2/2] input: mt: Document the MT event slot protocol (rev4)

Pavel Machek
2010-06-10T13:57:28Z

Hi!

> +Protocol Example A
> +------------------
> +
> +Here is what a minimal event sequence for a two-contact touch would look
> +like for a type A device:
> +
> + ABS_MT_POSITION_X x[0]
> + ABS_MT_POSITION_Y y[0]
> + SYN_MT_REPORT
> + ABS_MT_POSITION_X x[1]
> + ABS_MT_POSITION_Y y[1]
> + SYN_MT_REPORT
> + SYN_REPORT
...
> -Usage
> ------
> +Here is the sequence after lifting the first contact:
> +
> + ABS_MT_POSITION_X x[1]
> + ABS_MT_POSITION_Y y[1]
> + SYN_MT_REPORT
> + SYN_REPORT

...

> +Protocol Example B
> +------------------
> +
> +Here is what a minimal event sequence for a two-contact touch would look
> +like for a type B device:
> +
> + ABS_MT_SLOT 0
> + ABS_MT_TRACKING_ID 45
> + ABS_MT_POSITION_X x[0]
> + ABS_MT_POSITION_Y y[0]
> + ABS_MT_SLOT 1
> + ABS_MT_TRACKING_ID 46
> + ABS_MT_POSITION_X x[1]
> + ABS_MT_POSITION_Y y[1]
> + SYN_REPORT
> +
> +Here is the sequence after moving contact 45 in the x direction:
> +
> + ABS_MT_SLOT 0
> + ABS_MT_POSITION_X x[0]
> + SYN_REPORT

With this proposed system, protocol A is *very* different from
protocol B. Is there way to make them more similar?
--
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html