From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:51801 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758430Ab2C2QcR (ORCPT ); Thu, 29 Mar 2012 12:32:17 -0400 Date: Thu, 29 Mar 2012 11:32:06 -0500 From: Jonathan Nieder To: Andrew Morton Cc: Matthew Garrett , bhelgaas@google.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, stable@vger.kernel.org, Romain Francoise , Chris Holland , Colin Ian King , Hatem Masmoudi , janek Subject: [PATCH resend] ASPM: Fix pcie devices with non-pcie children Message-ID: <20120329163206.GA3480@burratino> References: <1332857861-11562-1-git-send-email-mjg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1332857861-11562-1-git-send-email-mjg@redhat.com> Sender: linux-pci-owner@vger.kernel.org List-ID: From: Matthew Garrett Date: Tue, 27 Mar 2012 10:17:41 -0400 Since 3.2.12 and 3.3, some systems are failing to boot with a BUG_ON. Some other systems using the pata_jmicron driver fail to boot because no disks are detected. Passing pcie_aspm=force on the kernel command line works around it. The cause: commit 4949be16822e ("PCI: ignore pre-1.1 ASPM quirking when ASPM is disabled") changed the behaviour of pcie_aspm_sanity_check() to always return 0 if aspm is disabled, in order to avoid cases where we changed ASPM state on pre-PCIe 1.1 devices. This skipped the secondary function of pcie_aspm_sanity_check which was to avoid us enabling ASPM on devices that had non-PCIe children, causing trouble later on. Move the aspm_disabled check so we continue to honour that scenario. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=42979 and http://bugs.debian.org/665420 [jn: with more symptoms in log message] Reported-by: Romain Francoise # kernel panic Reported-by: Chris Holland # disk detection trouble Signed-off-by: Matthew Garrett Cc: stable@vger.kernel.org Tested-by: Hatem Masmoudi # Dell Latitude E5520 Tested-by: janek # pata_jmicron with JMB362/JMB363 Signed-off-by: Jonathan Nieder --- Hi Andrew, This patch only appeared a couple of days ago[1], but it fixes a noticeable regression so I would like to make sure the patch becomes part of mainline and the 3.2.y- and 3.3.y-stable trees soon. Could you pick it up for linux-next until it makes its way to the PCI tree? Regression was introduced between 3.3-rc7 and 3.3 and between 3.2.11 and 3.2.12. Prevents boot on affected machines, though there is a workaround. Details about the symptoms and fix are above. Thanks, Jonathan [1] http://thread.gmane.org/gmane.linux.kernel.pci/14503 drivers/pci/pcie/aspm.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 4bdef24cd412..b500840a143b 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -508,9 +508,6 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev) int pos; u32 reg32; - if (aspm_disabled) - return 0; - /* * Some functions in a slot might not all be PCIe functions, * very strange. Disable ASPM for the whole slot @@ -519,6 +516,16 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev) pos = pci_pcie_cap(child); if (!pos) return -EINVAL; + + /* + * If ASPM is disabled then we're not going to change + * the BIOS state. It's safe to continue even if it's a + * pre-1.1 device + */ + + if (aspm_disabled) + continue; + /* * Disable ASPM for pre-1.1 PCIe device, we follow MS to use * RBER bit to determine if a function is 1.1 version device -- 1.7.10.rc1