Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762374AbZD3Jye (ORCPT ); Thu, 30 Apr 2009 05:54:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755365AbZD3JyY (ORCPT ); Thu, 30 Apr 2009 05:54:24 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:55798 "EHLO vavatch.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753316AbZD3JyW (ORCPT ); Thu, 30 Apr 2009 05:54:22 -0400 Date: Thu, 30 Apr 2009 10:54:14 +0100 From: Matthew Garrett To: Ingo Molnar Cc: "Darrick J. Wong" , Thomas Renninger , linux-kernel , cpufreq@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH v2] acpi: Fix regression where _PPC is not read at boot even when ignore_ppc=0 Message-ID: <20090430095414.GA19462@srcf.ucam.org> References: <20090415225348.GW8311@plum> <20090416002712.GX8311@plum> <200904161201.13409.trenn@suse.de> <20090416174217.GY8311@plum> <20090416224507.GA31984@srcf.ucam.org> <20090428193303.GC6968@plum> <20090428195348.GA8376@srcf.ucam.org> <20090429213930.GE6968@plum> <20090429220037.GA8604@srcf.ucam.org> <20090430072556.GD16737@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090430072556.GD16737@elte.hu> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: mjg59@codon.org.uk X-SA-Exim-Scanned: No (on vavatch.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1992 Lines: 54 On Thu, Apr 30, 2009 at 09:25:56AM +0200, Ingo Molnar wrote: > OTOH, if you rely on me figuring out which patch to revert and what > to do, it will take an indeterminate amount of time - together with > all the other items in my 'would be nice to hack on, given a bit of > free time' queue :) Here's Darrick's patch: Earlier, Ingo Molnar posted a patch to make it so that the kernel would avoid reading _PPC on his broken T60. Unfortunately, it seems that with Thomas Renninger's patch last July to eliminate _PPC evaluations when the processor driver loads, the kernel never actually reads _PPC at all! This is problematic if you happen to boot your non-T60 computer in a state where the BIOS _wants_ _PPC to be something other than zero. So, put the _PPC evaluation back into acpi_processor_get_performance_info if ignore_ppc isn't 1. This second version restores the correct function call, which simplifies the patch. I apologize for the churn and the poor eyesight. Signed-off-by: Darrick J. Wong --- drivers/acpi/processor_perflib.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index cafb410..85af717 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -348,7 +348,11 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr) if (result) goto update_bios; - return 0; + /* We need to call _PPC once when cpufreq starts */ + if (ignore_ppc != 1) + result = acpi_processor_get_platform_limit(pr); + + return result; /* * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that -- Matthew Garrett | mjg59@srcf.ucam.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/