Re: Power consumption HZ250 vs. HZ1000

From: Tony Lindgren
Date: Wed Jul 27 2005 - 06:22:00 EST


* Pavel Machek <pavel@xxxxxx> [050727 01:00]:
> Hi!
>
> > > USB devices prevent entering C3 and any interesting powersaving,
> > > try without USB...
> >
> > Why do USB devices prevent C3? If it was because of the timer polling
> > in the root hub, I believe that should be fixed now.
> >
> > Or is there some other reason?
>
> Yes. UHCI zas keeps doing DMA all the time.... It can be worked
> around, but it means proper usb powermanagment support.

OK, thanks for clarifying that.

Tony
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