commit: b8178f130e25c1bdac1c33e0996f1ff6e20ec08e
From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Date: Mon, 1 Apr 2013 15:47:39 -0600
Subject: 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 <bhelgaas@xxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # 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 0ac546d..c740364 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);
--
1.7.10.4
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