From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755936AbZBCRyV (ORCPT ); Tue, 3 Feb 2009 12:54:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753029AbZBCRyM (ORCPT ); Tue, 3 Feb 2009 12:54:12 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:46421 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752328AbZBCRyL (ORCPT ); Tue, 3 Feb 2009 12:54:11 -0500 Date: Tue, 3 Feb 2009 09:53:08 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: "Rafael J. Wysocki" cc: Benjamin Herrenschmidt , Linux Kernel Mailing List , Jesse Barnes , Andreas Schwab , Len Brown , Ingo Molnar Subject: Re: PCI PM: Restore standard config registers of all devices early In-Reply-To: <200902031026.34093.rjw@sisk.pl> Message-ID: References: <200901261904.n0QJ4Q9c016709@hera.kernel.org> <1233633061.16867.41.camel@pasglop> <200902031026.34093.rjw@sisk.pl> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 3 Feb 2009, Rafael J. Wysocki wrote: > > As I said, I tend to prefer the "loop of disable_irq()" approach, because it > would allow us to preserve the current ordering of ACPI operations. Namely, > if we do: > > suspend devices (normal suspend) > loop of disable_irq() > late suspend of devices > _PTS > disable nonboot CPUs > local_irq_disable() > sysdev suspend > enter sleep state > get control from the BIOS > sysdev resume > (*) > local_irq_enable() > enable nonboot CPUs > _WAK > early resume of devices > loop of enable_irq() > resume devices (normal resume) > > the ordering of _PTS with respect to putting devices into low power states and > disabling the nonboot CPUs will be the same as it is now and the same applies > to _WAK and putting devices into D0 etc. (I really _really_ wouldn't like to > change this ordering, since this alone is likely to break things badly). Yes. Also, make the "loop of disable/enable_irq()" phase be a helper function that also sets system_state to SYSTEM_SUSPENDING/SYSTEM_RUNNING respectively, and it should all be pretty clean, and the changes really should be pretty minimal. > Now, there's one subtle problem with resume in this picture. Namely, before > running the "early resume of devices" we have to make sure that the interrupts > will be masked. However, masking MSI-X, for example, means writing into > the memory space of the device, so we can't do it at this point. I really don't think it matters. Why? We simply don't care. All MSI-X things will still have to go through the regular irq layer, so the disable/enable_irq part, so even though we've done the "local_irq_enable()", we just don't care. Linus