From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753478Ab3AVHHK (ORCPT ); Tue, 22 Jan 2013 02:07:10 -0500 Received: from mga01.intel.com ([192.55.52.88]:36799 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752548Ab3AVHHI (ORCPT ); Tue, 22 Jan 2013 02:07:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,512,1355126400"; d="scan'208";a="280372043" Date: Tue, 22 Jan 2013 09:10:56 +0200 From: Mika Westerberg To: "Rafael J. Wysocki" Cc: ACPI Devel Maling List , LKML , Linux PM list , Lv Zheng Subject: Re: [PATCH 1/4] ACPI / PM: Make acpi_bus_init_power() more robust Message-ID: <20130122071056.GB2239@intel.com> References: <1792467.qHBR6KraFh@vostro.rjw.lan> <24285515.9Jp3KUo9Px@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <24285515.9Jp3KUo9Px@vostro.rjw.lan> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 22, 2013 at 03:09:01AM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > The ACPI specification requires the _PSC method to be present under > a device object if its power state cannot be inferred from the states > of power resources used by it (ACPI 5, Section 7.6.2). However, it > also requires that (for power states D0-D2 and D3hot) if the _PSn > (n = 0, 1, 2, 3) method is present under the device object, it also > must be executed after the power resources have been set > appropriately for the device to go into power state Dn (D3 means > D3hot in this case). Thus it is not clear from the specification > whether or not the _PSn method should be executed if the initial > configuraion of power resources used by the device indicates power > state Dn and the _PSC method is not present. > > The current implementation of acpi_bus_init_power() is based on the > assumption that it should not be necessary to execute _PSn in the > above situation, but experience shows that in fact that assumption > need not be satisfied. For this reason, make acpi_bus_init_power() > always execute _PSn if the initial configuration of device power > resources indicates power state Dn. > > Reported-by: Mika Westerberg You can add also, Tested-by: Mika Westerberg if you like. Thanks for fixing this.