[I hope I managed to not break the thread]

> Also, there's a small issue with polling frequency. hdapsd needs a
> fairly high frequency (say, 50Hz) to gather statistics and keep
> response latency low, whereas the hdaps driver's internal polling
> (routing to the input infrastructure) is currently done at only 20Hz.
> We'll need to increase the latter, thereby slightly increasing system
> load when hdaps isn't running.

Note that with AMS we're better off -- it has two interrupts telling us
when something is wrong.

Hence, most of the discussion about loads of input values only applies
to hdaps, the actual head-park functionality can be implemented with AMS
without ever reading any sensor values.

Hence we also need much less complexity in userland -- once an interrupt
comes in we trigger the hd park...

johannes