Re: Smart Battery System Design (was: Re: Question aboutuserspace-consumer)
From: Pavel Machek
Date: Sat Aug 15 2009 - 12:20:31 EST
Hi!
> > and wrt SBS, that would mean basically writing a driver for that Smart
> > Batery Charger and the Smart Battery devices creating means for some
> > entity to tell _start_charging_ based on the presence of a power source.
>
> For me the critical thing is that we ensure that the charger won't be
> left charging at anything more than a trickle charge when there's
> nothing monitoring the battery status. If the charger can do the SBS
> charger stuff autononmously it can look after itself (but the use of the
> regulator API becomes more questionable for those devices since the
> charger will be doing all the management of the regulators). If the SBS
> is done entirely in software the kernel at least needs to be able to
> notice the management software exiting and clean up after it, even if
> that's all it is able to do for itself.
Please don't put basic fastcharge logic to userspace:
* you still want to fastcharge at init=/bin/bash boot
* you want to fastcharge while machine is in s2ram. See spitz. Doing
that with userspace would be quite tricky.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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