From patchwork Mon Aug 6 01:34:28 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 175222 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 286462C0088 for ; Mon, 6 Aug 2012 11:35:38 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755425Ab2HFBei (ORCPT ); Sun, 5 Aug 2012 21:34:38 -0400 Received: from mga11.intel.com ([192.55.52.93]:16530 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755133Ab2HFBeh (ORCPT ); Sun, 5 Aug 2012 21:34:37 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP; 05 Aug 2012 18:34:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="193560356" Received: from yhuang-dev.sh.intel.com ([10.239.13.28]) by fmsmga001.fm.intel.com with ESMTP; 05 Aug 2012 18:34:35 -0700 From: Huang Ying To: Bjorn Helgaas Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Huang Ying , Alan Stern Subject: [BUGFIX -v2 2/4] PCI/PM: Keep parent bridge active when probing device Date: Mon, 6 Aug 2012 09:34:28 +0800 Message-Id: <1344216870-21105-3-git-send-email-ying.huang@intel.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1344216870-21105-1-git-send-email-ying.huang@intel.com> References: <1344216870-21105-1-git-send-email-ying.huang@intel.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org This patch fixes the following bug: http://marc.info/?l=linux-pci&m=134329923124234&w=2 The root cause of the bug is as follow. If a device is not bound with the corresponding driver, the device runtime PM will be disabled and the device will be put into suspended state. So that, the bridge/PCIe port connected to it may be put into suspended and low power state. When do probing for the device later, because the bridge/PCIe port connected to it is in low power state, the IO access to device may fail. To solve the issue, the bridge/PCIe port connected to the device is put into active state before probing. Reported-by: Bjorn Mork Signed-off-by: Huang Ying Reviewed-by: Rafael J. Wysocki --- drivers/pci/pci-driver.c | 6 ++++++ 1 file changed, 6 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -280,8 +280,12 @@ static long local_pci_probe(void *_ddi) { struct drv_dev_and_id *ddi = _ddi; struct device *dev = &ddi->dev->dev; + struct device *parent = dev->parent; int rc; + /* The parent bridge must be in active state when probing */ + if (parent) + pm_runtime_get_sync(parent); /* Unbound PCI devices are always set to disabled and suspended. * During probe, the device is set to enabled and active and the * usage count is incremented. If the driver supports runtime PM, @@ -298,6 +302,8 @@ static long local_pci_probe(void *_ddi) pm_runtime_set_suspended(dev); pm_runtime_put_noidle(dev); } + if (parent) + pm_runtime_put(parent); return rc; }