mjg59: Set _OSC supported field correctly (#638912)

1 files changed, 66 insertions, 0 deletions

diff --git a/pci-_osc-supported-field-should-contain-supported-features-not-enabled-ones.patch b/pci-_osc-supported-field-should-contain-supported-features-not-enabled-ones.patch
new file mode 100644
index 000000000..0baffd639
--- /dev/null
+++ b/pci-_osc-supported-field-should-contain-supported-features-not-enabled-ones.patch
@@ -0,0 +1,66 @@
+commit 885c252ffb059dc493200bdb981bdd21cabe4442
+Author: Matthew Garrett <mjg@redhat.com>
+Date:   Thu Dec 9 18:31:59 2010 -0500
+
+    PCI: _OSC "supported" field should contain supported features, not enabled ones
+    
+    From testing with Windows, the call to the PCI root _OSC method includes
+    the full set of features supported by the operating system even if the
+    hardware has already indicated that it doesn't support ASPM or MSI.
+    https://bugzilla.redhat.com/show_bug.cgi?id=638912 is a case where making
+    the _OSC call will incorrectly configure the chipset unless the supported
+    field has bits 1, 2 and 4 set. Rework the functionality to ensure that
+    we match this behaviour.
+    
+    Signed-off-by: Matthew Garrett <mjg@redhat.com>
+
+diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
+index 96668ad..afb5d08 100644
+--- a/drivers/acpi/pci_root.c
++++ b/drivers/acpi/pci_root.c
+@@ -450,7 +450,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
+ 	struct acpi_pci_root *root;
+ 	acpi_handle handle;
+ 	struct acpi_device *child;
+-	u32 flags, base_flags;
++	u32 flags;
+ 
+ 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
+ 	if (!root)
+@@ -498,10 +498,15 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
+ 	device->driver_data = root;
+ 
+ 	/*
+-	 * All supported architectures that use ACPI have support for
+-	 * PCI domains, so we indicate this in _OSC support capabilities.
++	 * Indicate support for various _OSC capabilities. These match
++	 * what the operating system supports, not what the hardware supports,
++	 * so they shouldn't be conditional on functionality that's been
++	 * blacklisted
+ 	 */
+-	flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
++	flags = OSC_EXT_PCI_CONFIG_SUPPORT | OSC_ACTIVE_STATE_PWR_SUPPORT |
++		OSC_CLOCK_PWR_CAPABILITY_SUPPORT |
++		OSC_PCI_SEGMENT_GROUPS_SUPPORT | OSC_MSI_SUPPORT;
++
+ 	acpi_pci_osc_support(root, flags);
+ 
+ 	/*
+@@ -555,17 +560,6 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
+ 	list_for_each_entry(child, &device->children, node)
+ 		acpi_pci_bridge_scan(child);
+ 
+-	/* Indicate support for various _OSC capabilities. */
+-	if (pci_ext_cfg_avail(root->bus->self))
+-		flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
+-	if (pcie_aspm_enabled())
+-		flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
+-			OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
+-	if (pci_msi_enabled())
+-		flags |= OSC_MSI_SUPPORT;
+-	if (flags != base_flags)
+-		acpi_pci_osc_support(root, flags);
+-
+ 	pci_acpi_add_bus_pm_notifier(device, root->bus);
+ 	if (device->wakeup.flags.run_wake)
+ 		device_set_run_wake(root->bus->bridge, true);