On Tue, Apr 09, 2013 at 03:05:25PM -0700, Greg KH wrote:
> I tried to apply the patch below to the 3.8-stable tree, but it has
> conflicts and doesn't apply. So I tried a straight-revert of
> 8c33f51df406e1a1f7fa4e9b244845b7ebd61fa6, which did work fine, but I
> noticed that it really doesn't look anything like the patch below.
>
> Is this patch a "logical" revert, and not a "literal" one?
>
> Anyway, can someone send me a properly backported version so it can be
> applied to the 3.8-stable tree?
Here's a literal revert for v3.8.
commit 59bf5ae30b63368cca7f1c16d1ecfeed37fd128e
Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Date: Tue Apr 9 16:22:21 2013 -0600
Revert "PCI/ACPI: Request _OSC control before scanning PCI root bus"
This reverts commit 8c33f51df406e1a1f7fa4e9b244845b7ebd61fa6.
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@xxxxxxxxxx>
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7928d4d..eb73798 100644
--- 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
