From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Guntsche Subject: Re: Processor C states and USB problem Date: Wed, 14 Jan 2004 16:34:37 +0100 Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <20040114163437.4bcbc62f.mike@it-loops.com> References: <3ACA40606221794F80A5670F0AF15F8401720CC9@PDSMSX403.ccr.corp.intel.com> <1074066934.9124.6.camel@ltspc67.epfl.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1074066934.9124.6.camel-TVkb0Wta32GnwOLKaxbZ/w@public.gmane.org> Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org On Wed, 14 Jan 2004 08:55:35 +0100 Diego SANTA CRUZ wrote: > On Wed, 2004-01-14 at 03:10, Yu, Luming wrote: > > > > > 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). > > > > > > > > > How did you know your processor never transition to C3 mode? > > > > The usage count is never above 5, even after a long period (an hour or > more of idle CPU). But yes, strictly speaking it's almost never ;-) > > > > > > 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] > > > > > > > > > Usage of C3 is 4. > > Yes, but compared to the usage count of C2 that is extremely low, and > the CPU is idling all the time (CPU usage is below 1%). I don't know > much about C states but I guess it should go into C3 much more often, > and the bus mastering activity should show something else than > ffffffff when booting with a bare bones kernel and with no extra hw > initialized(USB, FireWire, etc.) > Have you tried running a 2.6 kernel? Under 2.4 bus master always shows "ffffffff" on my notebook. Sometimes shutting down USB helps, sometimes it doesn't. Running under 2.6 I only get full bus master activity if an USB mouse is plugged in. /michael ------------------------------------------------------- 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