From patchwork Fri Jul 22 21:17:11 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Hilman X-Patchwork-Id: 1001052 Received: from smtp1.linux-foundation.org (smtp1.linux-foundation.org [140.211.169.13]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p6MLIkSL013182 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Fri, 22 Jul 2011 21:24:51 GMT Received: from daredevil.linux-foundation.org (localhost [127.0.0.1]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id p6MLH0uu020041; Fri, 22 Jul 2011 14:17:01 -0700 Received: from na3sys009aog109.obsmtp.com (na3sys009aog109.obsmtp.com [74.125.149.201]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with SMTP id p6MLGuFv020024 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 22 Jul 2011 14:16:58 -0700 Received: from mail-gx0-f178.google.com ([209.85.161.178]) (using TLSv1) by na3sys009aob109.postini.com ([74.125.148.12]) with SMTP ID DSNKTinoyDJFatgA+fNMy4iTqfAD44RzWOYY@postini.com; Fri, 22 Jul 2011 14:16:58 PDT Received: by mail-gx0-f178.google.com with SMTP id 8so1738259gxk.37 for ; Fri, 22 Jul 2011 14:16:56 -0700 (PDT) Received: by 10.68.10.69 with SMTP id g5mr3012964pbb.444.1311369416382; Fri, 22 Jul 2011 14:16:56 -0700 (PDT) Received: from localhost (c-24-19-7-36.hsd1.wa.comcast.net [24.19.7.36]) by mx.google.com with ESMTPS id b4sm2064695pba.59.2011.07.22.14.16.55 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 22 Jul 2011 14:16:55 -0700 (PDT) From: Kevin Hilman To: linux-pm@lists.linux-foundation.org Date: Fri, 22 Jul 2011 14:17:11 -0700 Message-Id: <1311369431-28775-1-git-send-email-khilman@ti.com> X-Mailer: git-send-email 1.7.6 Received-SPF: pass (localhost is always allowed.) X-Spam-Status: No, hits=-104.293 required=5 tests=AWL, BAYES_00, OSDL_HEADER_SPF_PASS, OSDL_HEADER_SUBJECT_BRACKETED, USER_IN_WHITELIST X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.21 Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [linux-pm] [RFC/PATCH] PM / Runtime: allow _put_sync() from interrupts-disabled context X-BeenThere: linux-pm@lists.linux-foundation.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: Linux power management List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Fri, 22 Jul 2011 21:25:35 +0000 (UTC) Currently the use of pm_runtime_put_sync() is not safe from interrupts-disabled context because rpm_idle() will release the spinlock and enable interrupts for the idle callbacks. This enables interrupts during a time where interrupts were expected to be disabled, and can have strange side effects on drivers that expected interrupts to be disabled. This is not a bug since the documentation clearly states that only _put_sync_suspend() is safe in IRQ-safe mode. However, pm_runtime_put_sync() could be made safe when in IRQ-safe mode by releasing the spinlock but not re-enabling interrupts, which is what this patch aims to do. Problem was found when using some buggy drivers that set pm_runtime_irq_safe() and used _put_sync() in interrupts-disabled context. The offending drivers have been fixed to use _put_sync_suspend(), But this patch is an RFC to see if it might make sense to allow using _put_sync() from interrupts-disabled context. Reported-by: Colin Cross Tested-by: Nishanth Menon Signed-off-by: Kevin Hilman --- drivers/base/power/runtime.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 8dc247c..acb3f83 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -226,11 +226,17 @@ static int rpm_idle(struct device *dev, int rpmflags) callback = NULL; if (callback) { - spin_unlock_irq(&dev->power.lock); + if (dev->power.irq_safe) + spin_unlock(&dev->power.lock); + else + spin_unlock_irq(&dev->power.lock); callback(dev); - spin_lock_irq(&dev->power.lock); + if (dev->power.irq_safe) + spin_lock(&dev->power.lock); + else + spin_lock_irq(&dev->power.lock); } dev->power.idle_notification = false;