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    SubjectRe: [linux-usb-devel] usb still sucks battery in -rc7-mm1
    Hi!

    > >I made some quick experiments, and usb still eats 4W of battery
    > >power. (With whole machine eating 9W, that's kind of a big deal)...
    > >
    > >This particular machine has usb bluetooth, but it can be disabled by
    > >firmware, and appears unplugged. (I did that). It also has fingerprint
    > >scanner, that can't be disabled, but that does not have driver (only
    > >driven by useland, and was unused in this experiment).
    > >
    > >Any ideas?
    >
    > (I have not followed the thread, so bear with me if I say anything
    > irrelavant)
    >
    > I have encountered at least 3 hubs (2 usb2 & 1 usb1) that will consume a
    > lot of power (about 2-2.5W if the laptop power consumption readings are to
    > be trusted) and heat up a lot (to the point of being too hot to touch for
    > more than a few seconds) even when no devices are connected, at least on
    > Linux. I have not tested them on a Windows machine to see if this is the
    > case there. The USB2 ones used Cypress chips. I do not know what your h/w
    > config is, but perhaps this is a similar case ?

    > PS: Note that the 2-2.5W consumption is the maximum that the laptop USB
    > port can provide, and I have noticed that with the hub's external power
    > supply connected it heats up even more.

    I'm not using any external hubs. I believe it is old "uhci keeps cpu
    from reaching deep c states" problem. I just want to ping greg/list,
    because greg told me problem is solved in -mm.
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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