From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934455Ab1JELeN (ORCPT ); Wed, 5 Oct 2011 07:34:13 -0400 Received: from rcsinet15.oracle.com ([148.87.113.117]:60084 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934397Ab1JELeL (ORCPT ); Wed, 5 Oct 2011 07:34:11 -0400 Message-ID: <4E8C40A8.6080205@oracle.com> Date: Wed, 05 Oct 2011 17:04:00 +0530 From: Ajaykumar Hotchandani User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Jesse Barnes , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] PCI: Set device power state to PCI_D0 for device without native PM support Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: rtcsinet22.oracle.com [66.248.204.30] X-CT-RefId: str=0001.0A090207.4E8C40B2.00A0,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org During test of one IB card with guest VM, found that, msi is not initialized properly. It turns out __write_msi_msg will do nothing if device current_state is not PCI_D0. And, that pci device does not have pm_cap in guest VM. There is an error in setting of power state to PCI_D0 in pci_enable_device(), but error is not returned for this. Following is code flow: pci_enable_device() --> __pci_enable_device_flags() --> do_pci_enable_device() --> pci_set_power_state() --> __pci_start_power_transition() We have following condition inside __pci_start_power_transition(): if (platform_pci_power_manageable(dev)) { error = platform_pci_set_power_state(dev, state); if (!error) pci_update_current_state(dev, state); } else { error = -ENODEV; /* Fall back to PCI_D0 if native PM is not supported */ if (!dev->pm_cap) dev->current_state = PCI_D0; } Here, from platform_pci_set_power_state(), acpi_pci_set_power_state() is getting called and that is failing with ENODEV because of following condition: if (!handle || ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0",&tmp))) return -ENODEV; Because of that, pci_update_current_state() is not getting called. With this patch, if device power state can not be set via platform_pci_set_power_state and that device does not have native pm support, then PCI device power state will be set to PCI_D0. Signed-off-by: Ajaykumar Hotchandani Signed-off-by: Yinghai Lu --- drivers/pci/pci.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e9651f0..ca8c82d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -664,6 +664,9 @@ static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state) error = platform_pci_set_power_state(dev, state); if (!error) pci_update_current_state(dev, state); + /* Fall back to PCI_D0 if native PM is not supported */ + else if (!dev->pm_cap) + dev->current_state = PCI_D0; } else { error = -ENODEV; /* Fall back to PCI_D0 if native PM is not supported */ -- 1.7.5.1