Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756249Ab3HWUFc (ORCPT ); Fri, 23 Aug 2013 16:05:32 -0400 Received: from charlotte.tuxdriver.com ([70.61.120.58]:39431 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754170Ab3HWUF3 (ORCPT ); Fri, 23 Aug 2013 16:05:29 -0400 Date: Fri, 23 Aug 2013 16:05:11 -0400 From: Neil Horman To: "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org, Len Brown , linux-acpi@vger.kernel.org, Bjorn Helgaas , Yinghai Lu , Linux PCI Subject: Re: [PATCH] ACPI: Fix osc flag setup ordering to allow pcie hotplug use when available Message-ID: <20130823200511.GB632@hmsreliant.think-freely.org> References: <1377278379-9054-1-git-send-email-nhorman@tuxdriver.com> <2074111.WRY7FfU4Ni@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2074111.WRY7FfU4Ni@vostro.rjw.lan> User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: -2.9 (--) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4913 Lines: 121 On Fri, Aug 23, 2013 at 09:38:18PM +0200, Rafael J. Wysocki wrote: > [CCs added] > > Please always send PCI-related material to linux-pci in the first place. > Sorry, I ran get_maintainers and it seemed to think linux-acpi was sufficient. > The change that broke things for you was actually intentional: > > commit b8178f130e25c1bdac1c33e0996f1ff6e20ec08e > Author: Bjorn Helgaas > Date: Mon Apr 1 15:47:39 2013 -0600 > > Revert "PCI/ACPI: Request _OSC control before scanning PCI root bus" > > This reverts commit 8c33f51df406e1a1f7fa4e9b244845b7ebd61fa6. > > so I think we'll need to clean up the ASMP initialization after all. > Crud. Reading over the revert commit, it seems like the problem boils down to the odering of checking aspm_disabled. It seems to me that the simple fix is to track the desire for acpi to disable aspm separately from the users desire to disable aspm (aspm_disabled). Then we just turn the points where we check the aspm_disabled into the appropriate or of two variables, except for pcie_asmp_sanity_check, which remains sensitive to just the user disable option. Or is there more to this? Neil > On Friday, August 23, 2013 01:19:39 PM Neil Horman wrote: > > Somewhere between 3.9 and 3.10 it seems the order in which pcie and acpi probed > > slots for hotplug capabilites got reversed. While this isn't a big deal, it did > > uncover a bug in the ACPI bus setup path. Specifically, acpi_pci_root_add calls > > pci_acpi_scan_root before setting the osc flags for the device handle. > > pci_acpi_scan_root, among other things uses device_is_managed_by_native_pciehp() > > to determine if a given slot has pcie hotplug capabilties, whcih checks the > > devices OSC_PCI_EXPRESS_NATIVE_HP_CONTROL flag. Since that flag is not set > > until after pci_acpi_scan_root_completes, the acpi code never sees that pcie > > slots are hotplug capable and configures them all to use acpi instead. > > > > Fix is pretty simple, just defer the scan until after the osc flags have been > > set on the device. Tested by myself and it seems to work well. > > > > Signed-off-by: Neil Horman > > CC: Len Brown > > CC: "Rafael J. Wysocki" > > CC: linux-acpi@vger.kernel.org > > --- > > drivers/acpi/pci_root.c | 41 ++++++++++++++++++++--------------------- > > 1 file changed, 20 insertions(+), 21 deletions(-) > > > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > > index 5917839..a2c2661 100644 > > --- a/drivers/acpi/pci_root.c > > +++ b/drivers/acpi/pci_root.c > > @@ -437,27 +437,6 @@ static int acpi_pci_root_add(struct acpi_device *device, > > flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT; > > acpi_pci_osc_support(root, flags); > > > > - /* > > - * TBD: Need PCI interface for enumeration/configuration of roots. > > - */ > > - > > - /* > > - * Scan the Root Bridge > > - * -------------------- > > - * Must do this prior to any attempt to bind the root device, as the > > - * PCI namespace does not get created until this call is made (and > > - * thus the root bridge's pci_dev does not exist). > > - */ > > - root->bus = pci_acpi_scan_root(root); > > - if (!root->bus) { > > - dev_err(&device->dev, > > - "Bus %04x:%02x not present in PCI namespace\n", > > - root->segment, (unsigned int)root->secondary.start); > > - result = -ENODEV; > > - goto end; > > - } > > - > > - /* Indicate support for various _OSC capabilities. */ > > if (pci_ext_cfg_avail()) > > flags |= OSC_EXT_PCI_CONFIG_SUPPORT; > > if (pcie_aspm_support_enabled()) { > > @@ -520,6 +499,26 @@ static int acpi_pci_root_add(struct acpi_device *device, > > "(_OSC support mask: 0x%02x)\n", flags); > > } > > > > + /* > > + * TBD: Need PCI interface for enumeration/configuration of roots. > > + */ > > + > > + /* > > + * Scan the Root Bridge > > + * -------------------- > > + * Must do this prior to any attempt to bind the root device, as the > > + * PCI namespace does not get created until this call is made (and > > + * thus the root bridge's pci_dev does not exist). > > + */ > > + root->bus = pci_acpi_scan_root(root); > > + if (!root->bus) { > > + dev_err(&device->dev, > > + "Bus %04x:%02x not present in PCI namespace\n", > > + root->segment, (unsigned int)root->secondary.start); > > + result = -ENODEV; > > + goto end; > > + } > > + > > pci_acpi_add_bus_pm_notifier(device, root->bus); > > if (device->wakeup.flags.run_wake) > > device_set_run_wake(root->bus->bridge, true); > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. > -- 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/