From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932281Ab3HWVaQ (ORCPT ); Fri, 23 Aug 2013 17:30:16 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:57922 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756490Ab3HWVaP (ORCPT ); Fri, 23 Aug 2013 17:30:15 -0400 From: "Rafael J. Wysocki" To: Bjorn Helgaas Cc: Neil Horman , "linux-kernel@vger.kernel.org" , Len Brown , "linux-acpi@vger.kernel.org" , Yinghai Lu , Linux PCI Subject: Re: [PATCH] ACPI: Fix osc flag setup ordering to allow pcie hotplug use when available Date: Fri, 23 Aug 2013 23:40:52 +0200 Message-ID: <4634097.MXvnqpQKZr@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.11.0-rc5+; KDE/4.9.5; x86_64; ; ) In-Reply-To: References: <1377278379-9054-1-git-send-email-nhorman@tuxdriver.com> <3958698.Gm9Wz19SSi@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, August 23, 2013 02:46:23 PM Bjorn Helgaas wrote: > 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. Well, do you have anything specific in mind? > But if you want to merge a patch along the lines of what Neil > proposes, I won't object. I'm not sure what to do really, so I'm asking. :-) Rafael > >> > 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. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.