From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757813AbZCBXNe (ORCPT ); Mon, 2 Mar 2009 18:13:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753487AbZCBXN0 (ORCPT ); Mon, 2 Mar 2009 18:13:26 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:33550 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbZCBXNZ convert rfc822-to-8bit (ORCPT ); Mon, 2 Mar 2009 18:13:25 -0500 From: "Rafael J. Wysocki" To: Arve =?iso-8859-1?q?Hj=F8nnev=E5g?= Subject: Re: [RFC][PATCH 1/4] PM: Rework handling of interrupts during suspend-resume (rev. 4) Date: Tue, 3 Mar 2009 00:13:01 +0100 User-Agent: KMail/1.11.0 (Linux/2.6.29-rc5-tst; KDE/4.2.0; x86_64; ; ) Cc: LKML , Linus Torvalds , Ingo Molnar , "Eric W. Biederman" , Benjamin Herrenschmidt , Jeremy Fitzhardinge , pm list , Len Brown , Jesse Barnes , Thomas Gleixner , Alan Stern , Johannes Berg References: <200902221837.49396.rjw@sisk.pl> <200903012324.39327.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200903030013.02805.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 03 March 2009, Arve Hjønnevåg wrote: > On Sun, Mar 1, 2009 at 2:24 PM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > Introduce two helper functions allowing us to prevent device drivers > > from getting any interrupts (without disabling interrupts on the CPU) > > during suspend (or hibernation) and to make them start to receive > > interrupts again during the subsequent resume, respectively. These > > functions make it possible to keep timer interrupts enabled while the > > "late" suspend and "early" resume callbacks provided by device > > drivers are being executed. > > > > Use these functions to rework the handling of interrupts during > > suspend (hibernation) and resume. Namely, interrupts will only be > > disabled on the CPU right before suspending sysdevs, while device > > drivers will be prevented from receiving interrupts, with the help of > > the new helper function, before their "late" suspend callbacks run > > (and analogously during resume). > > > > In addition, since the device interrups are now disabled before the > > CPU has turned all interrupts off and the CPU will ACK the interrupts > > setting the IRQ_PENDING bit for them, check in sysdev_suspend() if > > any wake-up interrupts are pending and abort suspend if that's the > > case. > > > > > > +void resume_device_irqs(void) > > +{ > > + struct irq_desc *desc; > > + int irq; > > + > > + for_each_irq_desc(irq, desc) > > + if (desc->status & IRQ_SUSPENDED) > > + enable_irq(irq); > > +} > > I think you need to clear IRQ_SUSPENDED here, not in enable_irq. enable_irq() clears IRQ_SUSPENDED. This has already been discussed btw. > > @@ -222,8 +222,9 @@ static void __enable_irq(struct irq_desc > > WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); > > break; > > case 1: { > > - unsigned int status = desc->status & ~IRQ_DISABLED; > > + unsigned int status; > > > > + status = desc->status & ~(IRQ_DISABLED | IRQ_SUSPENDED); > > /* Prevent probing on this irq: */ > > desc->status = status | IRQ_NOPROBE; > > check_irq_resend(desc, irq); > > This only clears IRQ_SUSPENDED if the interrupt was not disabled > elsewhere. If a driver calls interrupt_disable in suspend_late, but > calls interrupt_enable lazily, resume_device_irqs will reenable the > interrupt even though the driver has a disable reference. Then I'd regard the driver as buggy. > The rest of the patch looks good. I'm glad you like it. Thanks, Rafael