Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752245AbXLYCmG (ORCPT ); Mon, 24 Dec 2007 21:42:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751028AbXLYClz (ORCPT ); Mon, 24 Dec 2007 21:41:55 -0500 Received: from slackadelic.com ([65.196.224.53]:33031 "EHLO mail.slackadelic.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874AbXLYCly (ORCPT ); Mon, 24 Dec 2007 21:41:54 -0500 From: Carlos Corbacho To: Robert Hancock Subject: ACPI: _PTS ordering needs fixing for pre ACPI 3.0 systems (was: Re: x86: Increase PCIBIOS_MIN_IO to 0x1500 to fix nForce 4 suspend-to-RAM) Date: Tue, 25 Dec 2007 02:41:48 +0000 User-Agent: KMail/1.9.7 Cc: Linus Torvalds , "Rafael J. Wysocki" , "H. Peter Anvin" , Linux Kernel Mailing List , Greg KH , Ingo Molnar , Thomas Gleixner , Len Brown , Andrew Morton , pm list , linux-acpi@vger.kernel.org References: <4770356E.1000407@shaw.ca> <200712250003.27570.carlos@strangeworlds.co.uk> In-Reply-To: <200712250003.27570.carlos@strangeworlds.co.uk> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200712250241.49753.carlos@strangeworlds.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2781 Lines: 87 Adding Linux-ACPI to CC. On Tuesday 25 December 2007 00:03:25 Carlos Corbacho wrote: > According to the earlier versions of the ACPI spec, Linux is doing the > wrong thing - we should call _PTS() before we start powerding down devices, > or notifying device drivers to start suspending. > > So, my limited understanding of what we currently do for ACPI > suspend-to-RAM is: > > 1) Freeze processes/ devices > 2) Put all devices into low power mode > 3) Execute _PTS() > 4) Suspend system > > So the problem is - our current suspend order is fine for ACPI 3.0 and > above, but for pre-3.0 systems, this violates the older specs, where 2) and > 3) should be reversed. The following is a hack to illustrate what I'm getting at (this is tested on x86-64) (it's a hack since it does all the ACPI prepare bits during set_target() for the pre ACPI 3.0 systems, rather than prepare() - whether this can be cleaned up to move out just the _PTS() call, I don't know). It abuses suspend_ops->set_target(), but was the easiest way to quickly demonstrate this (since the kerneldoc for set_target() says it will always be executed before we suspend the devices). -Carlos --- drivers/acpi/sleep/main.c | 26 ++++++++++++++++++++++---- 1 files changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c index 96d23b3..89e708b 100644 --- a/drivers/acpi/sleep/main.c +++ b/drivers/acpi/sleep/main.c @@ -77,8 +77,19 @@ static int acpi_pm_set_target(suspend_state_t pm_state) } else { printk(KERN_ERR "ACPI does not support this state: %d\n", pm_state); - error = -ENOSYS; + return -ENOSYS; } + + /* + * For ACPI 1.0 and 2.0 systems, we must run the preparation methods + * before we put the devices into low power mode. + */ + if (acpi_gbl_FADT.header.revision < 3) { + error = acpi_sleep_prepare(acpi_target_sleep_state); + if (error) + acpi_target_sleep_state = ACPI_STATE_S0; + } + return error; } @@ -91,10 +102,17 @@ static int acpi_pm_set_target(suspend_state_t pm_state) static int acpi_pm_prepare(void) { - int error = acpi_sleep_prepare(acpi_target_sleep_state); + int error = 0; - if (error) - acpi_target_sleep_state = ACPI_STATE_S0; + /* + * For ACPI 3.0 or newer systems, we must run the preparation methods + * after we put the devices into low power mode. + */ + if (acpi_gbl_FADT.header.revision >= 3) { + error = acpi_sleep_prepare(acpi_target_sleep_state); + if (error) + acpi_target_sleep_state = ACPI_STATE_S0; + } return error; } -- 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/