On Fri, May 6, 2016 at 8:08 PM, Crestez Dan Leonard
<leonard.crestez@xxxxxxxxx> wrote:
>> In order to get the same precision in timestamps as
>> previously, where samples would be timestamped in the
>> poll function pf->timestamp when calling
>> iio_trigger_generic_data_rdy_poll() we introduce a
>> local timestamp in the sensor data, set it in the top half
>> (fastpath) of the interrupt handler and provide that to the
>> core when calling iio_push_to_buffers_with_timestamp().
>
> This doesn't work correctly with software timers. sdata->timestamp won't
> update because st_sensors_irq_handler doesn't get called in this mode.
>
> Easiest fix would be to set pollfunc->timestamp in
> st_sensors_irq_handler. But I don't really know how this is supposed to
> work.
Aha so it is implicit from the construction that whether it is a hardware
IRQ or a hrtimer, the top half must always update the timestamp in
pollfunc-timestamp, that was kind of hard to see :D
What the other threaded driver does is simply add the timestamp
in the trigger handler, like this:
iio_push_to_buffers_with_timestamp(indio_dev, buffer,
iio_get_time_ns());
But that pushes the timestamp away from the sampling time (when
the actual IRQ occurs) so I wanted to avoid that.
But maybe it has no bigger effect on anything anyways...
To updates pf->timestamp I probably need to patch a new function
into the trigger core that does only that. Will look into it.
Yours,
Linus Walleij
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