From: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
To: Jan Rychter <jan-JAsPCFd0eodBDgjK7y7TUQ@public.gmane.org>
Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: Processor states and USB
Date: Tue, 26 Nov 2002 14:59:34 +0100 [thread overview]
Message-ID: <20021126135934.GC1268@zaurus> (raw)
In-Reply-To: <m2el9eqb51.fsf-dTJq59+VGzkkCw8IV3R6h0EOCMrvLtNR@public.gmane.org>
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...
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next parent reply other threads:[~2002-11-26 13:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <m2el9eqb51.fsf@tnuctip.rychter.com>
[not found] ` <m2el9eqb51.fsf-dTJq59+VGzkkCw8IV3R6h0EOCMrvLtNR@public.gmane.org>
2002-11-26 13:59 ` Pavel Machek [this message]
2002-11-22 17:48 Processor states and USB Grover, Andrew
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