On Mon, Aug 03, 2020 at 08:51:58PM +0300, Vladimir Oltean wrote: > The current poll interval is enough to ensure that rising and falling > edge events are not lost for a 1 PPS signal with 50% duty cycle.
> Fix that by taking the following measures: > - Schedule the poll from a timer. Because we are really scheduling the > timer periodically, the extts events delivered to user space are > periodic too, and don't suffer from the "shift-to-the-right" effect. > - Increase the poll period to 6 times a second. This imposes a smaller > upper bound to the shift that can occur to the delivery time of extts > events, and makes user space (ts2phc) to always interpret correctly > which events should be skipped and which shouldn't. > - Move the SPI readout itself to the main PTP kernel thread, instead of > the generic workqueue. This is because the timer runs in atomic > context, but is also better than before, because if needed, we can > chrt & taskset this kernel thread, to ensure it gets enough priority > under load. Makes sense to me. Acked-by: Richard Cochran <richardcoch...@gmail.com>
