[ltp] Active Protection System

[Alejandro Bonilla Beeche]

On Tue, 2005-08-16 at 13:19 +0200, Lenz Grimmer wrote:
> Several components are involved here. There is an accelerometer that
> measures if the laptop is in motion. There now is an early version of a
> Linux kernel driver available on http://hdaps.sourceforge.net/ that
> allows applications to read out these acceleration values. However,
> there currently is no code available that actually takes proper action
> in case these values indicate a severe condition (like free fall). So
> currently, there is only partial support for what's known as the APS on
> Windows. What's missing is a *reliable* way to park the hard disk head
> and keep it parked (some sample code exists, but it does not seem to
> work for all drives). Oh, and the code that actually makes the decision
> if the accelerometer readings indicate that it's time to park the heads...
> 
> Bye,
> 	LenZ

Lenz,

	The code included in head_park actually works for most HD that have the
correct firmware and that quite actually work with HDAPS in Windows.
Yes, we need to add a timeout for the code at least right now that parks
the head for a certain amount of time. This is at the moment the key
that is holding us back. We already found a nice way to actually make a
daemon know when it should kick in. I'm still static in thinking that I
should add some laptop_mode features when we encounter soft movement on
the laptop. It will not park the head with soft movement, but will only
launch laptop_mode and then make things run in buffer and so... If
heavier movement is found, then we apply the head_park that should be
fixed. I will ask LKML now.

.Alejandro