From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368AbbBYViI (ORCPT ); Wed, 25 Feb 2015 16:38:08 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:62519 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752646AbbBYViG (ORCPT ); Wed, 25 Feb 2015 16:38:06 -0500 From: "Rafael J. Wysocki" To: Boris Brezillon Cc: Thomas Gleixner , Jason Cooper , Peter Zijlstra , Mark Rutland , linux-kernel@vger.kernel.org, Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH 1/3] genirq: prevent system wakeup when dealing with IRQF_NO_SUSPEND IRQs Date: Wed, 25 Feb 2015 23:01:31 +0100 Message-ID: <1721977.3MjzADDQbj@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.19.0+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1424771762-16343-2-git-send-email-boris.brezillon@free-electrons.com> References: <1424771762-16343-1-git-send-email-boris.brezillon@free-electrons.com> <1424771762-16343-2-git-send-email-boris.brezillon@free-electrons.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, February 24, 2015 10:56:00 AM Boris Brezillon wrote: > Mixing IRQF_NO_SUSPEND and !IRQF_NO_SUSPEND on the same IRQ line is highly > discouraged, but in some cases (IRQ shared by a timer and other devices) > you don't have any other choice. > Since some devices sharing the IRQ line might tag it as a wakeup source, > you might end up with your handler that requested IRQF_NO_SUSPEND not > being called in suspended state, or invalid system wakeup (the system is > woken up without any wakeup source actually requesting it). > > To deal with such unlikely situations, you'll have to: > 1/ prevent any automatic wakeup when at least one of the IRQ users > registered with IRQF_NO_SUSPEND > 2/ let IRQ users decide if/when they should wake the system up > > This patch is taking care of 1. > > Signed-off-by: Boris Brezillon > --- > kernel/irq/pm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c > index 3ca5325..1743162 100644 > --- a/kernel/irq/pm.c > +++ b/kernel/irq/pm.c > @@ -16,7 +16,8 @@ > > bool irq_pm_check_wakeup(struct irq_desc *desc) > { > - if (irqd_is_wakeup_armed(&desc->irq_data)) { > + if (irqd_is_wakeup_armed(&desc->irq_data) && > + !desc->no_suspend_depth) { > irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED); > desc->istate |= IRQS_SUSPENDED | IRQS_PENDING; > desc->depth++; > I'm not sure how this helps, because irqd_is_wakeup_armed() is false for IRQs having no_suspend_depth different from zero (please see the first check in suspend_device_irq()). -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.