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

Randy Dunlap
2010-05-23T23:46:38Z

On Mon, 24 May 2010 00:27:19 +0200 Henrik Rydberg wrote:

> Randy Dunlap wrote:
> [...]
> >> +Protocol Usage
> >> +--------------
> >> +
> >> +Contact details are sent sequentially as separate packets of ABS_MT
> >> +events. Only the ABS_MT events are recognized as part of a contact
> >> +packet. Since these events are ignored by current single-touch (ST)
> >> +applications, the MT protocol can be implemented on top of the ST protocol
> >> +in an existing driver.
> >> +
> >> +Drivers for type A devices mark the end of a packet by calling the
> >
> > end?
> >
> >> +input_mt_sync() function, which generates a SYN_MT_REPORT event. This
> >> +instructs the receiver to accept the data for the current contact and
> >> +prepare to receive another. Drivers for type B devices mark the beginning
> >
> > vs. beginning? Seems incongruous. And not just to the doc, but to
> > producers and consumers as well.
>
> Perhaps this modification makes it clearer?
>
> Drivers for type A devices separate contact packets by calling
> input_mt_sync() at the end of each packet. This generates a SYN_MT_REPORT
> event, which instructs the receiver to accept the data for the current
> contact and prepare to receive another.
>
> Drivers for type B devices separate contact packets by calling
> input_mt_slot(), with a slot as argument, at the beginning of each packet.
> This generates an ABS_MT_SLOT event, which instructs the receiver to
> prepare for updates of the given slot.

Yes, that sounds good to me.

> >> +of a packet by calling the input_mt_slot() function with a slot as
> >> +argument, which generates an ABS_MT_SLOT event. This instructs the receiver
> >> +to prepare for updates of the given slot.
> >> +
> >> +The end of a multi-touch transfer is marked by calling the usual
> >
> > The end method is done for Types A and B, right?
>
> How about this line instead?
>
> All drivers mark the end of a multi-touch transfer by calling the usual

Yes, good.

thanks.
---
~Randy
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