Re: [PATCH v4 14/14] HID: hid-multitouch: forwards MSC_TIMESTAMP

[Henrik Rydberg]

Hi Benjamin,

> Computes the device timestamp according to the specification.
> It also ensures that if the time between two events is greater
> than MAX_TIMESTAMP_INTERVAL, the timestamp will be reset.
> 
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx>
> ---

This was not what I envisioned from the discussion yesterday, I was
probably too vague. Firstly, the absolute time interval checked seems
to be 500 ms, which is arbitrary. Second, the wrap should probably use
(logical_maximum + 1). Third, we are still not sure whether we should
take the 'time = 0 means reset' logic literally, I think it needs to
be tested.

In light of this, I would like to suggest the patch below instead. It
should follow the current interpretation of the definition to the
letter. I imagine very few devices will actually do anything but wrap
the counter, but that remains to be seen. In that case, we could
simplify the code further, since we will have no hope of detecting
large intervals properly anyways.

Thanks,
Henrik