Revert "PCI/ACPI: Request _OSC control before scanning PCI root bus"

commit b8178f130e25c1bdac1c33e0996f1ff6e20ec08e upstream.

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 <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7928d4dc705618a833ccce3172ed5113307d4cff..eb737981c077b317cc04ea13636214ed5fc18c98 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -454,7 +454,6 @@ static int acpi_pci_root_add(struct acpi_device *device)
        acpi_handle handle;
        struct acpi_device *child;
        u32 flags, base_flags;
-       bool is_osc_granted = false;
 
        root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
        if (!root)
@@ -525,60 +524,6 @@ static int acpi_pci_root_add(struct acpi_device *device)
        flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
        acpi_pci_osc_support(root, flags);
 
-       /* Indicate support for various _OSC capabilities. */
-       if (pci_ext_cfg_avail())
-               flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
-       if (pcie_aspm_support_enabled()) {
-               flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
-               OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
-       }
-       if (pci_msi_enabled())
-               flags |= OSC_MSI_SUPPORT;
-       if (flags != base_flags) {
-               status = acpi_pci_osc_support(root, flags);
-               if (ACPI_FAILURE(status)) {
-                       dev_info(&device->dev, "ACPI _OSC support "
-                               "notification failed, disabling PCIe ASPM\n");
-                       pcie_no_aspm();
-                       flags = base_flags;
-               }
-       }
-       if (!pcie_ports_disabled
-           && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
-               flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
-                       | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
-                       | OSC_PCI_EXPRESS_PME_CONTROL;
-
-               if (pci_aer_available()) {
-                       if (aer_acpi_firmware_first())
-                               dev_dbg(&device->dev,
-                                       "PCIe errors handled by BIOS.\n");
-                       else
-                               flags |= OSC_PCI_EXPRESS_AER_CONTROL;
-               }
-
-               dev_info(&device->dev,
-                       "Requesting ACPI _OSC control (0x%02x)\n", flags);
-
-               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);
-               } 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);
-               }
-       } 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.
         */
@@ -618,14 +563,66 @@ static int acpi_pci_root_add(struct acpi_device *device)
        list_for_each_entry(child, &device->children, node)
                acpi_pci_bridge_scan(child);
 
-       /* ASPM setting */
-       if (is_osc_granted) {
-               if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM)
-                       pcie_clear_aspm(root->bus);
+       /* Indicate support for various _OSC capabilities. */
+       if (pci_ext_cfg_avail())
+               flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
+       if (pcie_aspm_support_enabled())
+               flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
+                       OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
+       if (pci_msi_enabled())
+               flags |= OSC_MSI_SUPPORT;
+       if (flags != base_flags) {
+               status = acpi_pci_osc_support(root, flags);
+               if (ACPI_FAILURE(status)) {
+                       dev_info(root->bus->bridge, "ACPI _OSC support "
+                               "notification failed, disabling PCIe ASPM\n");
+                       pcie_no_aspm();
+                       flags = base_flags;
+               }
+       }
+
+       if (!pcie_ports_disabled
+           && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
+               flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
+                       | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
+                       | OSC_PCI_EXPRESS_PME_CONTROL;
+
+               if (pci_aer_available()) {
+                       if (aer_acpi_firmware_first())
+                               dev_dbg(root->bus->bridge,
+                                       "PCIe errors handled by BIOS.\n");
+                       else
+                               flags |= OSC_PCI_EXPRESS_AER_CONTROL;
+               }
+
+               dev_info(root->bus->bridge,
+                       "Requesting ACPI _OSC control (0x%02x)\n", flags);
+
+               status = acpi_pci_osc_control_set(device->handle, &flags,
+                                       OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
+               if (ACPI_SUCCESS(status)) {
+                       dev_info(root->bus->bridge,
+                               "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 {
+                       dev_info(root->bus->bridge,
+                               "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 {
-               pr_info("ACPI _OSC control for PCIe not granted, "
-                       "disabling ASPM\n");
-               pcie_no_aspm();
+               dev_info(root->bus->bridge,
+                        "Unable to request _OSC control "
+                        "(_OSC support mask: 0x%02x)\n", flags);
        }
 
        pci_acpi_add_bus_pm_notifier(device, root->bus);