From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Pogadl Subject: [BUG, REGRESSION] ACPI: Set _PDC Date: Thu, 17 Jun 2010 00:40:24 +0200 Message-ID: <201006170040.24736.pogadl.jan@googlemail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:34260 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754808Ab0FPWke (ORCPT ); Wed, 16 Jun 2010 18:40:34 -0400 Received: by fxm10 with SMTP id 10so1184952fxm.19 for ; Wed, 16 Jun 2010 15:40:32 -0700 (PDT) Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-acpi@vger.kernel.org Cc: achiang@hp.com Hi, with commit commit 5d554a7bb0643a6151a84319bfeba8270bf5269e (ACPI: processor: add internal processor_physically_present()) a new function got introduced which always fails on machines with CONFIG_SMP disabled. Thus _PDC will never be initialized? set?. The problem of the processor_physically_present() is, that it calls the acpi_get_cpuid(...) function which returns on NON-SMP machines always -1. Note that i don't have any real knowledge what _PDC actualy realy do, all i gatherd so far is that its for switching C-Stats. I Stumbled across this by bisecting the problem, that the undervolting patches from linux-phc.org aren't working anymore with 2.6.34 (2.6.35-rc3). Whereas they worked fine with 2.6.33 on my Samsung X20 Notebook with a Pentium M precossor. The acpi-cpufreq is now using System-IO instead of MSR Registers. Since i don't know what should be the correct behaviour here i can't provide any patches. But i doub't it's the correct behaviour of processor_physically_present() to always fail on non-SMP machines. Deleting the function call, to this new function in early_init_pdc(...), and i get back the old behaviour. cheers, jan