From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756745AbZE3Hk5 (ORCPT ); Sat, 30 May 2009 03:40:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751371AbZE3Hku (ORCPT ); Sat, 30 May 2009 03:40:50 -0400 Received: from mail-qy0-f130.google.com ([209.85.221.130]:36629 "EHLO mail-qy0-f130.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750939AbZE3Hku convert rfc822-to-8bit (ORCPT ); Sat, 30 May 2009 03:40:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=irY7X/VfiKCEnnl/Fxe52EA7GoNBkSRov3g3wT4nPUUX3zIhGjDQKBEyCZpitWQr81 P+mevSJtuUN6vRbKiiIxO5opeqbzYxvyfkZB+OOPFTS0E4it94e61SW/qFdwtUio7kNb jll0TzLYSc2K1/d+LYviIVK4ueP/hlAgDwsfA= MIME-Version: 1.0 In-Reply-To: <4d34a0a70905300034q1dee8febl60b5213082e3a5d1@mail.gmail.com> References: <1241483224-7113-1-git-send-email-khilman@deeprootsystems.com> <200905232214.57186.rjw@sisk.pl> <4A1A4297.50809@samsung.com> <200905300135.07103.rjw@sisk.pl> <4d34a0a70905300034q1dee8febl60b5213082e3a5d1@mail.gmail.com> From: Kim Kyuwon Date: Sat, 30 May 2009 16:40:31 +0900 Message-ID: <4d34a0a70905300040w49deb457rc4eb1122db8eed62@mail.gmail.com> Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs To: "Rafael J. Wysocki" Cc: Kim Kyuwon , Andrew Morton , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Ingo Molnar , Kyungmin Park , Linus Torvalds , Kevin Hilman Content-Type: text/plain; charset=EUC-KR Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 30, 2009 at 4:34 PM, Kim Kyuwon wrote: > On Sat, May 30, 2009 at 8:35 AM, Rafael J. Wysocki wrote: >> On Monday 25 May 2009, Kim Kyuwon wrote: >>> Rafael J. Wysocki wrote: >>> > On Saturday 23 May 2009, Kim Kyuwon wrote: >>> >> On Sat, May 23, 2009 at 7:29 AM, Rafael J. Wysocki wrote: >>> >>> On Saturday 23 May 2009, Kim Kyuwon wrote: >>> > [--snip--] >>> >>>> You changed the really important part of Linux, which may affect most >>> >>>> processor architectures. I think you should be careful. If some of >>> >>>> architectures can't take care of it (they can implement >>> >>>> disable_irq_wake correctly in H/W level, will you revert your changes? >>> >>> No, the changes are not going to be reverted. In fact things should have been >>> >>> done like this already much earlier. >>> >>> >>> >>> Now, do you have any particular example of a problem related to these changes >>> >>> or is it only a theoretical issue? >>> >> I'd CCing you when I'm sending a mail for this particular example of a example. >>> >> http://markmail.org/thread/fvt7d62arofon5xx >>> > >>> > Well, as I said above, reverting the changes that introduced >>> > [suspend|resume]_device_irqs() is not an option, becuase it was the only sane >>> > way to achieve the goal they were added for. So, we need to fix the wake-up >>> > problem on your platform with the assumption that >>> > [suspend|resume]_device_irqs() are going to stay. >>> > >>> > For starters, would it be possible to teach the 'disable' hook of your >>> > platform's interrupt controller not to mask the IRQs that have both >>> > IRQ_WAKEUP and IRQ_SUSPENDED set? That apparently would work around the >>> > wake-up interrupts problem. >>> >>> Thank you for considering this issue and spending your time. In order to >>> make your idea work, we need to add a dummy 'set_wake' hook which >>> returns always zero. Anyway, IMO, I think your idea is good to work >>> around this problem. But Kevin Hilman(OMAP PM Maintainer) would make >>> final decision. >>> >>> Buy the way, how can you handle the problem that a few interrupt are >>> discarded in a small window? I can be sure they are discarded, because I >>> have debugged defects which generate in sleep/resume state hundreds of >>> times on ARM Processors(PXA310, S3C6410, OMAP3430). Wake-up interrupts >>> are generated as soon as arch_suspend_enable_irqs() invoked. >> >> Sorry for the delayed response. >> >> If the wake-up interrupts are not masked, they will be delivered to the drivers >> as soon as arch_suspend_enable_irqs() has run. So, if the drivers are able to >> handle them at this point (ie. before resume_device_irqs() is called), they >> won't be lost. > > Thank you for your response! > > Your suspend_device_irqs() disables all IRQs(except timer IRQ) while > entering suspend. i.e. Before invoking resume_device_irqs() or > resume_noirq callback, all IRQs(except timer IRQ) is in IRQ_DISABLED > status. Right? > But if an IRQ is in IRQ_DISABLED status, its interrupt handler can be Sorry: *Can't be* > invoked. (As you know, all IRQs with IRQ_DISABLE are not handled in > handle_level_irq function). Thus, even if the wake-up interrupts are > not masked, the drivers are not able to handle interrupts, because the > interrupt handler can't be invoked due to IRQ_DISABLED set by > suspend_device_irqs(). > >> The only problem I see is that the drivers may expect their >> ->resume_noirq() callbacks to be executed first. > > resume_noirq() callbacks are also invoked after arch_suspend_enable_irqs(). > > Regards, > Kyuwon > -- Kyuwon (±Ô¿ø)