Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756097Ab2HOTrr (ORCPT ); Wed, 15 Aug 2012 15:47:47 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:54868 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751918Ab2HOTrp (ORCPT ); Wed, 15 Aug 2012 15:47:45 -0400 MIME-Version: 1.0 In-Reply-To: <201205242245.45888.rjw@sisk.pl> References: <201205242245.45888.rjw@sisk.pl> From: Bjorn Helgaas Date: Wed, 15 Aug 2012 13:47:23 -0600 Message-ID: Subject: Re: [PATCH] PCI / ACPI: Do not request control of ASPM if the BIOS has disabled it To: "Rafael J. Wysocki" , Len Brown Cc: ACPI Devel Mailing List , LKML , linux-pci@vger.kernel.org, Wei Kong , Jean Delvare , Matthew Garrett Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2125 Lines: 51 On Thu, May 24, 2012 at 2:45 PM, Rafael J. Wysocki wrote: > 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. Len, since you've applied recent patches in this area, can you take care of this, too? > --- > 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 -- 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/