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: 1001042 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p6MLHCfR017035 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 22 Jul 2011 21:17:38 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QkN5j-0003Ne-7F; Fri, 22 Jul 2011 21:17:03 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QkN5i-00022i-Qf; Fri, 22 Jul 2011 21:17:02 +0000 Received: from na3sys009aog101.obsmtp.com ([74.125.149.67]) by canuck.infradead.org with smtps (Exim 4.76 #1 (Red Hat Linux)) id 1QkN5f-00022O-JM for linux-arm-kernel@lists.infradead.org; Fri, 22 Jul 2011 21:17:00 +0000 Received: from mail-pz0-f44.google.com ([209.85.210.44]) (using TLSv1) by na3sys009aob101.postini.com ([74.125.148.12]) with SMTP ID DSNKTinoyDJFatgA+fNMy4iTqfAD44RzWOYY@postini.com; Fri, 22 Jul 2011 14:16:59 PDT Received: by mail-pz0-f44.google.com with SMTP id 5so4803659pzk.3 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 Subject: [RFC/PATCH] PM / Runtime: allow _put_sync() from interrupts-disabled context 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 X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110722_171659_870186_A9591895 X-CRM114-Status: GOOD ( 13.30 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [74.125.149.67 listed in list.dnswl.org] Cc: Nishanth Menon , linux-omap@vger.kernel.org, Colin Cross , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Fri, 22 Jul 2011 21:17:38 +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;