From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karol Kozimor Subject: C3 support w/o ARB_DIS (P4-M on i845) Date: Wed, 12 May 2004 12:25:27 +0200 Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <20040512102527.GA8050@hell.org.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 Return-path: Content-Disposition: inline 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 Hi, I've just noticed that FADT shows: P_LVL2_LAT: 90 P_LVL3_LAT: 300 for my P4-M processor, whereas /proc/acpi/processor/*/power shows: active state: C2 default state: C1 bus master activity: 00000000 states: C1: promotion[C2] demotion[--] latency[000] usage[00294320] *C2: promotion[--] demotion[C1] latency[090] usage[02552774] C3: and /proc/acpi/processor/*/info shows: processor id: 0 acpi id: 1 bus mastering control: no power management: yes throttling control: yes performance management: yes limit interface: yes So, it seems there is some C3 support, but it is not used due to lack of bus-mastering control (PM2_CNT_BLK is 0). However, the flags section in the FADT indicates that WBINVD is supported. The comment in processor.c says the possibility of using C3 in the absence of ARB_DIS must be investigated. What is the current status? Any obvious caveats for implementation? Best regards, -- Karol 'sziwan' Kozimor sziwan-DETuoxkZsSqrDJvtcaxF/A@public.gmane.org ------------------------------------------------------- This SF.Net email is sponsored by Sleepycat Software Learn developer strategies Cisco, Motorola, Ericsson & Lucent use to deliver higher performing products faster, at low TCO. http://www.sleepycat.com/telcomwpreg.php?From=osdnemail3