From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757895Ab2EXUko (ORCPT ); Thu, 24 May 2012 16:40:44 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:35699 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752563Ab2EXUkn (ORCPT ); Thu, 24 May 2012 16:40:43 -0400 From: "Rafael J. Wysocki" To: Bjorn Helgaas Subject: [PATCH] PCI / ACPI: Do not request control of ASPM if the BIOS has disabled it Date: Thu, 24 May 2012 22:45:45 +0200 User-Agent: KMail/1.13.6 (Linux/3.4.0+; KDE/4.6.0; x86_64; ; ) Cc: ACPI Devel Mailing List , LKML , linux-pci@vger.kernel.org, Len Brown , Wei Kong , Jean Delvare , Matthew Garrett MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201205242245.45888.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki We want to report that the kernel supports ASPM to the BIOS even if the BIOS signals us that it doesn't. So, we need the flags to include (OSC_ACTIVE_STATE_PWR_SUPPORT | OSC_CLOCK_PWR_CAPABILITY_SUPPORT) before calling acpi_pci_osc_support(root, flags) in acpi_pci_root_add() (unless there's a command line telling us that ASPM is not to be supported). However, knowing that the BIOS doesn't support ASPM, we shouldn't request the control of it, so we should remove (OSC_ACTIVE_STATE_PWR_SUPPORT | OSC_CLOCK_PWR_CAPABILITY_SUPPORT) from the flags before calling acpi_pci_osc_control_set() in those cases. Failing to do so causes the evaluation of _OSC for the PCI root bridge to return error codes on some systems where it should work correctly. Reported-and-tested-by: Wei Kong Signed-off-by: Rafael J. Wysocki --- -stable material, I think. Thanks, Rafael --- drivers/acpi/pci_root.c | 4 ++++ 1 file changed, 4 insertions(+) Index: linux/drivers/acpi/pci_root.c =================================================================== --- linux.orig/drivers/acpi/pci_root.c +++ linux/drivers/acpi/pci_root.c @@ -574,6 +574,10 @@ static int __devinit acpi_pci_root_add(s if (flags != base_flags) acpi_pci_osc_support(root, flags); + if (!pcie_aspm_enabled()) + flags &= ~(OSC_ACTIVE_STATE_PWR_SUPPORT | + OSC_CLOCK_PWR_CAPABILITY_SUPPORT); + if (!pcie_ports_disabled && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) { flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL