From b8178f130e25c1bdac1c33e0996f1ff6e20ec08e Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 1 Apr 2013 15:47:39 -0600 Subject: [PATCH] Revert "PCI/ACPI: Request _OSC control before scanning PCI root bus" This reverts commit 8c33f51df406e1a1f7fa4e9b244845b7ebd61fa6. Conflicts: drivers/acpi/pci_root.c This commit broke some pre-1.1 PCIe devices by leaving them with ASPM enabled. Previously, we had disabled ASPM on these devices because many of them don't implement it correctly (per 149e1637). Requesting _OSC control early means that aspm_disabled may be set before we scan the PCI bus and configure link ASPM state. But the ASPM configuration currently skips the check for pre-PCIe 1.1 devices when aspm_disabled is set, like this: acpi_pci_root_add acpi_pci_osc_support if (flags != base_flags) pcie_no_aspm aspm_disabled = 1 pci_acpi_scan_root ... pcie_aspm_init_link_state pcie_aspm_sanity_check if (!aspm_disabled) /* check for pre-PCIe 1.1 device */ Therefore, setting aspm_disabled early means that we leave ASPM enabled on these pre-PCIe 1.1 devices, which is a regression for some devices. The best fix would be to clean up the ASPM init so we can evaluate _OSC before scanning the bug (that way boot-time and hot-add discovery will work the same), but that requires significant rework. For now, we'll just revert the _OSC change as the lowest-risk fix. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=55211 Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki Acked-by: Yinghai Lu CC: stable@vger.kernel.org # v3.8+ --- drivers/acpi/pci_root.c | 76 ++++++++++++++++++++--------------------- 1 file changed, 37 insertions(+), 39 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 0ac546d5e53f..c740364d4abe 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -415,7 +415,6 @@ static int acpi_pci_root_add(struct acpi_device *device, struct acpi_pci_root *root; struct acpi_pci_driver *driver; u32 flags, base_flags; - bool is_osc_granted = false; root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL); if (!root) @@ -476,6 +475,30 @@ 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. + */ + + mutex_lock(&acpi_pci_root_lock); + list_add_tail(&root->node, &acpi_pci_roots); + mutex_unlock(&acpi_pci_root_lock); + + /* + * 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) { + printk(KERN_ERR PREFIX + "Bus %04x:%02x not present in PCI namespace\n", + root->segment, (unsigned int)root->secondary.start); + result = -ENODEV; + goto out_del_root; + } + /* Indicate support for various _OSC capabilities. */ if (pci_ext_cfg_avail()) flags |= OSC_EXT_PCI_CONFIG_SUPPORT; @@ -494,6 +517,7 @@ static int acpi_pci_root_add(struct acpi_device *device, flags = base_flags; } } + if (!pcie_ports_disabled && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) { flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL @@ -514,54 +538,28 @@ static int acpi_pci_root_add(struct acpi_device *device, status = acpi_pci_osc_control_set(device->handle, &flags, OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); if (ACPI_SUCCESS(status)) { - is_osc_granted = true; dev_info(&device->dev, "ACPI _OSC control (0x%02x) granted\n", flags); + if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) { + /* + * We have ASPM control, but the FADT indicates + * that it's unsupported. Clear it. + */ + pcie_clear_aspm(root->bus); + } } else { - is_osc_granted = false; dev_info(&device->dev, "ACPI _OSC request failed (%s), " "returned control mask: 0x%02x\n", acpi_format_exception(status), flags); + pr_info("ACPI _OSC control for PCIe not granted, " + "disabling ASPM\n"); + pcie_no_aspm(); } } else { dev_info(&device->dev, - "Unable to request _OSC control " - "(_OSC support mask: 0x%02x)\n", flags); - } - - /* - * TBD: Need PCI interface for enumeration/configuration of roots. - */ - - mutex_lock(&acpi_pci_root_lock); - list_add_tail(&root->node, &acpi_pci_roots); - mutex_unlock(&acpi_pci_root_lock); - - /* - * 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) { - printk(KERN_ERR PREFIX - "Bus %04x:%02x not present in PCI namespace\n", - root->segment, (unsigned int)root->secondary.start); - result = -ENODEV; - goto out_del_root; - } - - /* ASPM setting */ - if (is_osc_granted) { - if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) - pcie_clear_aspm(root->bus); - } else { - pr_info("ACPI _OSC control for PCIe not granted, " - "disabling ASPM\n"); - pcie_no_aspm(); + "Unable to request _OSC control " + "(_OSC support mask: 0x%02x)\n", flags); } pci_acpi_add_bus_pm_notifier(device, root->bus); -- 2.20.1