Re: [ACPI] Processor states and USB

[Pavel M. <pa...@uc...>]

Hi!

> My CPU has the following states:
> 
>     C1:                  promotion[C2] demotion[--] latency[000] usage[00100920]
>     C2:                  promotion[C3] demotion[C1] latency[001] usage[06199483]
>    *C3:                  promotion[--] demotion[C2] latency[100] usage[12803374]
> 
> Now, whenever the usb-uhci module is loaded, C3 never gets
> used. C2 is the only state that my CPU is in. If I unload usb-uhci, the
> machine starts using C3.
> 
> Somebody explained to me that this is because the usb-uhci driver uses
> DMA transfers to talk to the hardware and poll it for new devices. Is
> there a patch available that changes this behavior? Anybody found any
> solutions to this?

UHCI is crap,  and this will be hard to solve.
You should have seen what it does with
system performance in FSBR mode....

usb-devel is better place for this discussion...

-- 
				Pavel
Written on sharp zaurus, because my Velo1 broke. If you have Velo you don't need...