From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kok, Auke" Subject: bug? acpi p-state + ondemand keeps dropping max freq Date: Thu, 05 Jun 2008 15:30:56 -0700 Message-ID: <48486920.4040006@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mga11.intel.com ([192.55.52.93]:63004 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754570AbYFEWcl (ORCPT ); Thu, 5 Jun 2008 18:32:41 -0400 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-acpi@vger.kernel.org, Linux Kernel Mailing List Cc: "Brown, Len" , cpufreq@lists.linux.org.uk, Dave Jones I've consistently experienced the following bizarre problem since 2.6.20, all the way up to 2.6.25.3 (regressed yesterday and each of these kernels exposes this behaviour): /sys/devices/system/cpu/cpu0/cpufreq # grep . * affected_cpus:0 cpuinfo_cur_freq:800000 cpuinfo_max_freq:1866000 cpuinfo_min_freq:800000 scaling_available_frequencies:1866000 1600000 1333000 1066000 800000 scaling_available_governors:ondemand performance scaling_cur_freq:800000 scaling_driver:acpi-cpufreq scaling_governor:ondemand scaling_max_freq:800000 scaling_min_freq:800000 Notice that scaling_mx_freq dropped down to the lowest possible value and as such my CPU is only working at 800MHz. At boot time this field properly displays 1866MHz and everything works OK. After a certain period (?) this value drops down and I cannot manually elevate it back to the normal level: # echo 1866000 > scaling_max_freq ; cat scaling_max_freq 800000 # echo 1866000 > scaling_max_freq ; cat scaling_max_freq 800000 This renders my Dothan to utterly poor speeds. (standard T43) performance cpufreq governor makes no difference - I still can't change the frequency upper/lower values. Auke