From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758961Ab2GLJqO (ORCPT ); Thu, 12 Jul 2012 05:46:14 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:37219 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753231Ab2GLJqM (ORCPT ); Thu, 12 Jul 2012 05:46:12 -0400 From: "Rafael J. Wysocki" To: Greg KH Subject: [PATCH] PM / Runtime: Do not increment device usage counts before probing Date: Thu, 12 Jul 2012 11:51:48 +0200 User-Agent: KMail/1.13.6 (Linux/3.5.0-rc5+; KDE/4.6.0; x86_64; ; ) Cc: Linux PM list , LKML , Alan Stern , Kevin Hilman MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201207121151.48819.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki The pm_runtime_get_noresume() calls before really_probe() and before executing __device_attach() for each driver on the device's bus cause problems to happen if probing fails and if the driver has enabled runtime PM for the device in its .probe() callback. Namely, in that case, if the device has been resumed by the driver after enabling its runtime PM and if it turns out that .probe() should return an error, the driver is supposed to suspend the device and disable its runtime PM before exiting .probe(). However, because the device's runtime PM usage counter was incremented by the core before calling .probe(), the driver's attempt to suspend the device will not succeed and the device will remain in the full-power state after the failing .probe() has returned. To fix this issue, remove the pm_runtime_get_noresume() calls from driver_probe_device() and from device_attach() and replace the corresponding pm_runtime_put_sync() calls with pm_runtime_idle() to preserve the existing behavior (which is to check if the device is idle and to suspend it eventually in that case after probing). Reported-and-tested-by: Kevin Hilman Reviewed-by: Kevin Hilman Signed-off-by: Rafael J. Wysocki --- drivers/base/dd.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) Index: linux/drivers/base/dd.c =================================================================== --- linux.orig/drivers/base/dd.c +++ linux/drivers/base/dd.c @@ -356,10 +356,9 @@ int driver_probe_device(struct device_dr pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); - pm_runtime_get_noresume(dev); pm_runtime_barrier(dev); ret = really_probe(dev, drv); - pm_runtime_put_sync(dev); + pm_runtime_idle(dev); return ret; } @@ -406,9 +405,8 @@ int device_attach(struct device *dev) ret = 0; } } else { - pm_runtime_get_noresume(dev); ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); - pm_runtime_put_sync(dev); + pm_runtime_idle(dev); } out_unlock: device_unlock(dev);