From patchwork Fri Jan 30 22:25:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 5753101 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id A11999F38B for ; Fri, 30 Jan 2015 22:26:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 16B2B20219 for ; Fri, 30 Jan 2015 22:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62E09201CE for ; Fri, 30 Jan 2015 22:26:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751700AbbA3WZ7 (ORCPT ); Fri, 30 Jan 2015 17:25:59 -0500 Received: from cantor2.suse.de ([195.135.220.15]:38473 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750908AbbA3WZ6 (ORCPT ); Fri, 30 Jan 2015 17:25:58 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 33194AC20; Fri, 30 Jan 2015 22:25:57 +0000 (UTC) Date: Sat, 31 Jan 2015 09:25:45 +1100 From: NeilBrown To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, GTA04 owners , linux-pm@vger.kernel.org, Kalle Jokiniemi Subject: [PATCH] IRQ: don't suspend nested_thread irqs over system suspend. Message-ID: <20150131092545.33ed35b8@notabene.brown> X-Mailer: Claws Mail 3.10.1-162-g4d0ed6 (GTK+ 2.24.25; x86_64-suse-linux-gnu) MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, T_TVD_MIME_EPI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Nested IRQs can only fire when the parent irq fires. So when the parent is suspended, there is no need to suspend the child irq. Suspending nested irqs can cause a problem is they are suspended or resumed in the wrong order. If an interrupt fires while the parent is active but the child is suspended, then the interrupt will not be acknowledged properly and so an interrupt storm can result. This is particularly likely if the parent is resumed before the child, and the interrupt was raised during suspend. Ensuring correct ordering would be possible, but it is simpler to just never suspend nested interrupts. This patch does that. This patch allows the IRQF_EARLY_RESUME to be removed from twl4030_sih_setup(). That flag attempts to fix the same problem is a very different way, but causes [ 56.095825] WARNING: CPU: 0 PID: 3 at ../kernel/irq/manage.c:661 irq_nested_primary_handler+0x18/0x28() [ 56.095825] Primary handler called for nested irq 348 warnings on resume. Signed-off-by: NeilBrown diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c index 3ca532592704..40cbcfb7fc43 100644 --- a/kernel/irq/pm.c +++ b/kernel/irq/pm.c @@ -118,6 +118,8 @@ void suspend_device_irqs(void) unsigned long flags; bool sync; + if (irq_settings_is_nested_thread(desc)) + continue; raw_spin_lock_irqsave(&desc->lock, flags); sync = suspend_device_irq(desc, irq); raw_spin_unlock_irqrestore(&desc->lock, flags); @@ -158,6 +160,8 @@ static void resume_irqs(bool want_early) if (!is_early && want_early) continue; + if (irq_settings_is_nested_thread(desc)) + continue; raw_spin_lock_irqsave(&desc->lock, flags); resume_irq(desc, irq);