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

Henrik Rydberg
2010-05-23T22:28:03Z

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.

>> +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

> is

Changed, thanks.

Henrik