From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: Fwd: [Bug 92111] Power regression from 3.17 to 3.18 and 3.19 Date: Wed, 11 Feb 2015 00:42:12 +0000 Message-ID: <20150211004212.GA14030@srcf.ucam.org> References: <1790277.SYbcblnshn@vostro.rjw.lan> <1721194.3W9qJruT3Q@vostro.rjw.lan> <20150211003318.GA13680@srcf.ucam.org> <3544719.NIea3H3XJ4@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:41484 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750868AbbBKAmS (ORCPT ); Tue, 10 Feb 2015 19:42:18 -0500 Content-Disposition: inline In-Reply-To: <3544719.NIea3H3XJ4@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Andreas Noever , ACPI Devel Maling List , attila.jakosa@gmail.com, Len Brown On Wed, Feb 11, 2015 at 02:02:06AM +0100, Rafael J. Wysocki wrote: > On Wednesday, February 11, 2015 12:33:18 AM Matthew Garrett wrote: > > We're using intel_idle, so we should be making idle state determination > > regardless of what ACPI tells us. So is Darwin mode influencing the > > state of some MSR that controls whether PC6 can be entered? > > I need to confirm that with Len, but I don't recall there being an MSR > controlling the PC6 availability on Haswell. There is one for PC7, but > not for PC6 IIRC. Ok. > > Is the GPU blocking it because of some configuration difference? > > That is possible. I know that it has some say in things here. > > I don't know enough about how the chip decides to enter PC6 to be able to > > tell. > > Well, so honestly how do you expect me to respond here? We really need feedback from people who know how the CPU makes its PC6 determination - the firmware has clearly done something differently, but without knowing what factors feed into that determination we're pretty much helpless. -- Matthew Garrett | mjg59@srcf.ucam.org