Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932146Ab3HWUqq (ORCPT ); Fri, 23 Aug 2013 16:46:46 -0400 Received: from mail-ie0-f178.google.com ([209.85.223.178]:45302 "EHLO mail-ie0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756025Ab3HWUqo (ORCPT ); Fri, 23 Aug 2013 16:46:44 -0400 MIME-Version: 1.0 In-Reply-To: <3958698.Gm9Wz19SSi@vostro.rjw.lan> References: <1377278379-9054-1-git-send-email-nhorman@tuxdriver.com> <2074111.WRY7FfU4Ni@vostro.rjw.lan> <20130823200511.GB632@hmsreliant.think-freely.org> <3958698.Gm9Wz19SSi@vostro.rjw.lan> From: Bjorn Helgaas Date: Fri, 23 Aug 2013 14:46:23 -0600 Message-ID: Subject: Re: [PATCH] ACPI: Fix osc flag setup ordering to allow pcie hotplug use when available To: "Rafael J. Wysocki" Cc: Neil Horman , "linux-kernel@vger.kernel.org" , Len Brown , "linux-acpi@vger.kernel.org" , Yinghai Lu , Linux PCI Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5884 Lines: 135 On Fri, Aug 23, 2013 at 2:53 PM, Rafael J. Wysocki wrote: > On Friday, August 23, 2013 04:05:11 PM Neil Horman wrote: >> 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? > > No, I think you're right. > > Bjorn, what do you think? My opinion is that the _OSC/ASPM state management is ridiculously complicated already, and this would make it slightly more complicated. That's why my preference would be to attempt a more radical cleanup and simplification instead of adding another wart. But if you want to merge a patch along the lines of what Neil proposes, I won't object. Bjorn >> > 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/