From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85466C4151A for ; Wed, 30 Jan 2019 22:53:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3335220863 for ; Wed, 30 Jan 2019 22:53:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548888833; bh=NzuS+MG33DEOM10pKtwDtAgfBO5NRSbCeEq9QzMpiqs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rTT/S1vuZpl9AE4Grgq7JHLFrG3mZfM9nlSYWfrVwo4mCFHdAO9TglHB8Dh3IvPGw PJvNlt7IEpbdzTvmLNr8XXckEWlU3pBM0+6ZH48oIOI8Jbc72rctyswhhaL3eB00AL ogiBXEIADUi+KvawsvE5bZm/MS8G/nw5sRvMGs2Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730115AbfA3Wxw (ORCPT ); Wed, 30 Jan 2019 17:53:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:41296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725890AbfA3Wxw (ORCPT ); Wed, 30 Jan 2019 17:53:52 -0500 Received: from localhost (unknown [69.71.4.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CA9B4218AF; Wed, 30 Jan 2019 22:44:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548888258; bh=NzuS+MG33DEOM10pKtwDtAgfBO5NRSbCeEq9QzMpiqs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Zadjk9nreaRVcVtlcrY6ptc/lB9ibHvuqJQio2J6vm8v3aEZJlFDa8rklqmuUTYdm ZvRHOblVWPMYDRDPFpjyD9M3CxoHg+Q3mhfdEKobPNGlhFijXezZ8b1k6R2HBp+wkx RX5elDjHRgkwU8JfH3nHaTbJIEUIHNu32s/724zY= Date: Wed, 30 Jan 2019 16:44:15 -0600 From: Bjorn Helgaas To: Aaron Sierra Cc: linux-pci@vger.kernel.org, "Rafael J. Wysocki" , Len Brown Subject: Re: [PATCH v2 1/2] PCI/ACPI: Move _OSC test for native services to top Message-ID: <20190130224415.GK229773@google.com> References: <1539642186-12821-1-git-send-email-asierra@xes-inc.com> <1540483292-24049-1-git-send-email-asierra@xes-inc.com> <1540483292-24049-2-git-send-email-asierra@xes-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1540483292-24049-2-git-send-email-asierra@xes-inc.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Aaron, On Thu, Oct 25, 2018 at 11:01:31AM -0500, Aaron Sierra wrote: > Move the simple test for when PCIe native services are disabled > closer to the top, prior to where things get more complicated. > > Signed-off-by: Aaron Sierra > --- > drivers/acpi/pci_root.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index 707aafc..eb9f14e 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -441,6 +441,12 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, > return; > } > > + if (pcie_ports_disabled) { > + dev_info(&device->dev, > + "PCIe port services disabled; not requesting _OSC control\n"); > + return; > + } Today we always set "*no_aspm = 1" if _OSC fails, which means we later call pcie_no_aspm(). After this patch, when pcie_ports_disabled is "true", we don't even try to evaluate _OSC, and we will never set *no_aspm, so we will never call pcie_no_aspm() when pcie_ports_disabled is "true", which happens in these cases: 1) CONFIG_PCIEPORTBUS is unset, or 2) CONFIG_PCIEPORTBUS=y and we booted with "pcie_ports=compat" Case 1) isn't a problem because pcie_no_aspm() is only implemented when CONFIG_PCIEASPM=y, and CONFIG_PCIEASPM depends on CONFIG_PCIEPORTBUS, so in this case today we only call the empty stub pcie_no_aspm() function. But case 2) is a behavior change that seems unintended. Even though CONFIG_PCIEASPM depends on CONFIG_PCIEPORTBUS, ASPM doesn't actually *use* anything provided by PCIEPORTBUS, so I think the ASPM code is still active and useful even when we boot with "pcie_ports=compat". Whether CONFIG_PCIEASPM should depend on CONFIG_PCIEPORTBUS is another question. I tend to think maybe it should not, but that's an orthogonal question. > /* > * All supported architectures that use ACPI have support for > * PCI domains, so we indicate this in _OSC support capabilities. > @@ -468,11 +474,6 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, > return; > } > > - if (pcie_ports_disabled) { > - dev_info(&device->dev, "PCIe port services disabled; not requesting _OSC control\n"); > - return; > - } > - > if ((support & ACPI_PCIE_REQ_SUPPORT) != ACPI_PCIE_REQ_SUPPORT) { > decode_osc_support(root, "not requesting OS control; OS requires", > ACPI_PCIE_REQ_SUPPORT); > -- > 2.7.4 >