From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Slagter Subject: No c2-c7 states on core i7 Date: Fri, 20 Nov 2009 15:28:56 +0100 Message-ID: <4B06A7A8.109@slagter.name> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eriks.xs4all.nl ([83.160.41.216]:53857 "EHLO eriks.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753216AbZKTOl4 (ORCPT ); Fri, 20 Nov 2009 09:41:56 -0500 Received: from nemesis.slagter.name (nemesis-eth0.ipv4.slagter.name [10.1.7.2]) by nemesis.slagter.name (Postfix) with ESMTP id A3C6E3B4E6 for ; Fri, 20 Nov 2009 15:28:56 +0100 (CET) Received: from artemis.slagter.name (artemis-vlan7.ipv6.slagter.name [IPv6:2001:888:133a:107::1]) by nemesis.slagter.name (Postfix) with ESMTP for ; Fri, 20 Nov 2009 15:28:56 +0100 (CET) Received: from [IPv6:2001:888:133a:103::2] (skylla.ipv6.slagter.name [IPv6:2001:888:133a:103::2]) by artemis.slagter.name (Postfix) with ESMTP id 64CF73930B86 for ; Fri, 20 Nov 2009 15:28:56 +0100 (CET) Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-acpi@vger.kernel.org Hi there, I already put on my flame retardant underwear, I know this is a FAQ, but I really need a bit of a jumpstart, google won't tell me where to start, so please be gentle ;-) I bought a Gigabyte EX58-UD3R motherboard recently and put a core i7 920 on it. This seems to be a fairly common combination. In short: I know the core i7 does implement several C-states, from memory c1, c1e, c3, c6 and c7. Linux (vanilla, 2.6.31.6) does not recognise any of them. The kernel configuration is very similar to the one I am running on my laptop with a recent mobile core2duo processor, and this one reports C1,C2,C3 (although it should also report yet another C state, but I guess that one is disabled by the bios or something alike). Is this normal (WIP?)? If not, where should I start debugging? I know there is "something" with decoding the DSDT table, but what should I look for? I seem to remember that with an earlier linux version (before 2.6.30.5) it actually did work, but I am not completely sure. Thanks for your help in advance! Additional info that might be useful: - all options related to power saving and C-states are ENABLED in the BIOS - all options related to power management and idling are ENABLED in the kernel, which runs in 64 bits mode - frequency switching runs fine using acpi-cpufreq and ondemand governor If I compare the dmesg from both computers after booting, the laptop says "ACPI: CPU1 (power states: C1[C1] C2[C2] C3[C3])" at some point, this message is not output at all by the server. Output from proc/acpi/processor/CPU0/info processor id: 0 acpi id: 0 bus mastering control: yes power management: no throttling control: yes limit interface: yes Output from proc/acpi/processor/CPU0/power active state: C0 max_cstate: C8 maximum allowed latency: 2000000000 usec states: C1: type[C1] promotion[--] demotion[--] latency[000] usage[00000000] duration[00000000000000000000]