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    SubjectRe: Question about userspace-consumer
    Hi!

    > On Mon, Aug 10, 2009 at 10:58:01PM +0100, Mark Brown wrote:
    > > On Mon, Aug 10, 2009 at 11:05:54PM +0300, Felipe Balbi wrote:
    > >
    > > > I was reading userspace-consumer file ad was wondering whether would be
    > > > possible to use that in order to implement what SBS-IF [1] proposes
    > > > using sbs-enabled devices.
    > >
    > > Looking at that I'm not sure why you wish to push this into user space?
    >
    > we need some daemon monitoring battery statuses and taking actions on
    > that. Imagine, for example, usb charging where we can:
    >
    > a. charge up to 100mA when unconfigured
    > b. charge up to 500mA when configured
    > c. charge up to 2.5A when with dedicated charger
    > d. charge up to 2.5mA when bus is suspended
    >
    > handling all of those cases on kernel space seems a little bit odd,
    > especially because we still need to take care of state-of-charge,
    > pack temperature, time-to-charge, etc etc etc.
    >
    > a big looping polling for that stuff in kernel space didn't seem ok to
    > me.

    As battery charging is done by hw on many common machines... yes it is
    okay to do in kernel.

    > > Like I say, from a quick read through of the specs I'm not sure that I'd
    > > push this into user space but I've not thought about this deeply and may
    > > be missing something.
    >
    > I think kernel should, as long as possible, only provide functionalities
    > for userland to take decisions and actions, no ?
    >
    > Handling policy in kernel space I find it a little odd, specially
    > because different manufacturers might have different charging algorithms
    > they want to implement.

    I don't see what policy you see in battery charging. There is
    basically single battery chemistry in use, so this is not as complex
    as you paint it...

    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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