Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754076Ab2FTQr2 (ORCPT ); Wed, 20 Jun 2012 12:47:28 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:41502 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753943Ab2FTQr0 convert rfc822-to-8bit (ORCPT ); Wed, 20 Jun 2012 12:47:26 -0400 MIME-Version: 1.0 In-Reply-To: References: <1340158627-7586-1-git-send-email-msb@chromium.org> Date: Wed, 20 Jun 2012 09:47:24 -0700 Message-ID: Subject: Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort From: Mandeep Baines To: Alan Stern Cc: linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Mandeep Singh Baines , linux-pm@vger.kernel.org, stable@kernel.org, Pavel Machek , Len Brown , Greg Kroah-Hartman , Kevin Hilman , Colin Cross , Sameer Nanda , Olof Johansson Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3003 Lines: 88 On Wed, Jun 20, 2012 at 7:58 AM, Alan Stern wrote: > On Tue, 19 Jun 2012, Mandeep Singh Baines wrote: > >> __device_suspend() must always send a completion. Otherwise, parent >> devices will wait forever. >> >> Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and >> system sleep (v2)", introduced a regression by short-circuiting the >> complete_all() for certain error cases. >> >> This patch fixes the bug by always signalling a completion. >> >> Addresses http://crosbug.com/31972 >> >> Tested by injecting an abort via the following patch: >> >> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c >> index a004db3..e5a6fce 100644 >> --- a/drivers/usb/core/hcd-pci.c >> +++ b/drivers/usb/core/hcd-pci.c >> @@ -21,6 +21,7 @@ >> ?#include >> ?#include >> ?#include >> +#include >> >> ?#include >> ?#include >> @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event) >> >> ?static int hcd_pci_suspend(struct device *dev) >> ?{ >> + ? ? ? if (!strcmp("0000:00:1d.3", dev_name(dev))) >> + ? ? ? ? ? ? ? return -EBUSY; >> ? ? ? ? return suspend_common(dev, device_may_wakeup(dev)); >> ?} > > When you include one patch in front of another like this, doesn't it > confuse the automatic tools? ?You might end up getting both changes > include in the final commit. ?:-) > Ah. Good point. Removed the test code and re-sent. >> ?drivers/base/power/main.c | ? ?6 ++++-- >> ?1 files changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c >> index e0fb5b0..9cb845e 100644 >> --- a/drivers/base/power/main.c >> +++ b/drivers/base/power/main.c >> @@ -1031,7 +1031,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) >> ? ? ? dpm_wait_for_children(dev, async); >> >> ? ? ? if (async_error) >> - ? ? ? ? ? ? return 0; >> + ? ? ? ? ? ? goto Complete; >> >> ? ? ? pm_runtime_get_noresume(dev); >> ? ? ? if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) >> @@ -1040,7 +1040,7 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) >> ? ? ? if (pm_wakeup_pending()) { >> ? ? ? ? ? ? ? pm_runtime_put_sync(dev); >> ? ? ? ? ? ? ? async_error = -EBUSY; >> - ? ? ? ? ? ? return 0; >> + ? ? ? ? ? ? goto Complete; >> ? ? ? } >> >> ? ? ? device_lock(dev); >> @@ -1097,6 +1097,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) >> ? ? ? } >> >> ? ? ? device_unlock(dev); >> + >> + Complete: >> ? ? ? complete_all(&dev->power.completion); >> >> ? ? ? if (error) { > > Otherwise this looks right to me. > > Acked-by: Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/