From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754112Ab0IBCz0 (ORCPT ); Wed, 1 Sep 2010 22:55:26 -0400 Received: from smtp-out.google.com ([216.239.44.51]:8542 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753026Ab0IBCzZ (ORCPT ); Wed, 1 Sep 2010 22:55:25 -0400 From: Colin Cross To: linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org Cc: Colin Cross , Pavel Machek , "Rafael J. Wysocki" , Len Brown , Greg Kroah-Hartman , Alan Stern , Randy Dunlap , Andrew Morton Subject: [PATCH] PM: Prevent waiting forever on asynchronous resume after abort Date: Wed, 1 Sep 2010 19:54:12 -0700 Message-Id: <1283396052-3620-1-git-send-email-ccross@android.com> X-Mailer: git-send-email 1.7.1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Only wait on a parent device during resume if the parent device is suspended. Consider three drivers, A, B, and C. The parent of A is C, and C has async_suspend set. On boot, C->power.completion is initialized to 0. During the first suspend: suspend_devices_and_enter(...) dpm_resume(...) device_suspend(A) device_suspend(B) returns error, aborts suspend dpm_resume_end(...) dpm_resume(...) device_resume(A) dpm_wait(A->parent == C) wait_for_completion(C->power.completion) The wait_for_completion will never complete, because complete_all(C->power.completion) will only be called from device_suspend(C) or device_resume(C), neither of which is called if suspend is aborted before C. After a successful suspend->resume cycle, where B doesn't abort suspend, C->power.completion is left in the completed state by the call to device_resume(C), and the same call path will work if B aborts suspend. Signed-off-by: Colin Cross --- drivers/base/power/main.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index cb784a0..e159910 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -526,7 +526,8 @@ static int device_resume(struct device *dev, pm_message_t state, bool async) TRACE_DEVICE(dev); TRACE_RESUME(0); - dpm_wait(dev->parent, async); + if (dev->parent && dev->parent->power.status >= DPM_OFF) + dpm_wait(dev->parent, async); device_lock(dev); dev->power.status = DPM_RESUMING; -- 1.7.1