RE: Processor C states and USB problem

[Diego SANTA CRUZ <Diego.SantaCruz-p8DiymsW2f8@public.gmane.org>]

On Fri, 2004-01-09 at 11:05, Petr Olivka wrote:
> in 2.4 kernel I have to unload all usb modules. Then power drop to C3
> state. If I remember, only usbcore can be loaded (on my D600).
> 

But even booting with init=/bin/sh and without ever loading any USB
module I get permanent bus mastering activity. Any ideas?

Diego

> poli
> 
> 
> On Fri, 9 Jan 2004, Diego SANTA CRUZ wrote:
> 
> > Hi,
> >
> > I picked up this thread and I'm interested in knowing a bit more about
> > bus mastering and C3, as my laptop never goes into C3. I own a Dell
> > Inspiron 8500 (details at
> > http://ltswww.epfl.ch/~dsanta/resources/dell-i8500-linux).
> >
> > This is what I get for the power states:
> > # cat /proc/acpi/processor/CPU0/power
> > active state:            C2
> > default state:           C1
> > bus master activity:     ffffffff
> > states:
> >     C1:                  promotion[C2] demotion[--] latency[000] usage[00039800]
> >    *C2:                  promotion[C3] demotion[C1] latency[050] usage[00573330]
> >     C3:                  promotion[--] demotion[C2] latency[050] usage[00000004]
> >
> > I tried booting with init=/bin/sh and manually loading the processor
> > module, without any external hardware attached, so that no special
> > hardware is initialized, but still there is non-stopping bus mastering
> > activity. What could be causing it? Any ideas how could I find out?
> >
> > BTW, I'm running the latest Fedora Core 1 kernel (2.4.22-1.2140.nptl)
> >
> > Thanks for any info,
> >
> > Diego
> >
> > On Mon, 2004-01-05 at 10:06, Li, Shaohua wrote:
> > > Hi,
> > > C3 is a kind of idle, it means deep power saving.
> > > Actually, I observed the same symptom as you: USB devices caused many bus master activities, which make processor can't enter C3.
> > >
> > > Thanks,
> > > Shaohua
> >
> > --
> > -------------------------------------------------------
> > Diego Santa Cruz - PhD
> > Publications available at http://ltswww.epfl.ch/~dsanta
> > Signal Processing Institute (LTS1 / ITS / STI)
> > Swiss Federal Institute of Technology (EPFL)
> > EPFL - STI - ITS, CH-1015 Lausanne, Switzerland
> > E-mail:     Diego.SantaCruz-p8DiymsW2f8@public.gmane.org
> > Phone:      +41 - 21 - 693 26 57
> > Fax:        +41 - 21 - 693 76 00
> > -------------------------------------------------------
> >
> >
> >
> > -------------------------------------------------------
> > This SF.net email is sponsored by: Perforce Software.
> > Perforce is the Fast Software Configuration Management System offering
> > advanced branching capabilities and atomic changes on 50+ platforms.
> > Free Eval! http://www.perforce.com/perforce/loadprog.html
> > _______________________________________________
> > Acpi-devel mailing list
> > Acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> > https://lists.sourceforge.net/lists/listinfo/acpi-devel
> >
-- 
-------------------------------------------------------
Diego Santa Cruz - PhD
Publications available at http://ltswww.epfl.ch/~dsanta
Signal Processing Institute (LTS1 / ITS / STI)
Swiss Federal Institute of Technology (EPFL)
EPFL - STI - ITS, CH-1015 Lausanne, Switzerland
E-mail:     Diego.SantaCruz-p8DiymsW2f8@public.gmane.org
Phone:      +41 - 21 - 693 26 57
Fax:        +41 - 21 - 693 76 00
-------------------------------------------------------



-------------------------------------------------------
This SF.net email is sponsored by: Perforce Software.
Perforce is the Fast Software Configuration Management System offering
advanced branching capabilities and atomic changes on 50+ platforms.
Free Eval! http://www.perforce.com/perforce/loadprog.html