diff options
Diffstat (limited to 'pci-acpi-disable-aspm-if-no-osc.patch')
| -rw-r--r-- | pci-acpi-disable-aspm-if-no-osc.patch | 53 |
1 files changed, 0 insertions, 53 deletions
diff --git a/pci-acpi-disable-aspm-if-no-osc.patch b/pci-acpi-disable-aspm-if-no-osc.patch deleted file mode 100644 index 044f38964..000000000 --- a/pci-acpi-disable-aspm-if-no-osc.patch +++ /dev/null @@ -1,53 +0,0 @@ -From: Matthew Garrett <mjg@redhat.com> -Subject: ACPI: Disable ASPM if the platform won't provide _OSC control for PCIe - -ACPI: Disable ASPM if the platform won't provide _OSC control for PCIe - -The PCI SIG documentation for the _OSC OS/firmware handshaking interface -states: - -"If the _OSC control method is absent from the scope of a host bridge -device, then the operating system must not enable or attempt to use any -features defined in this section for the hierarchy originated by the host -bridge." - -The obvious interpretation of this is that the OS should not attempt to use -PCIe hotplug, PME or AER - however, the specification also notes that an -_OSC method is *required* for PCIe hierarchies, and experimental validation -with An Alternative OS indicates that it doesn't use any PCIe functionality -if the _OSC method is missing. That arguably means we shouldn't be using -MSI or extended config space, but right now our problems seem to be limited -to vendors being surprised when ASPM gets enabled on machines when other -OSs refuse to do so. So, for now, let's just disable ASPM if the _OSC -method doesn't exist or refuses to hand over PCIe capability control. - -Signed-off-by: Matthew Garrett <mjg@redhat.com> ---- - -diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c -index 4eac593..1f67057 100644 ---- a/drivers/acpi/pci_root.c -+++ b/drivers/acpi/pci_root.c -@@ -33,6 +33,7 @@ - #include <linux/pm_runtime.h> - #include <linux/pci.h> - #include <linux/pci-acpi.h> -+#include <linux/pci-aspm.h> - #include <linux/acpi.h> - #include <linux/slab.h> - #include <acpi/acpi_bus.h> -@@ -543,6 +544,14 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device) - if (flags != base_flags) - acpi_pci_osc_support(root, flags); - -+ status = acpi_pci_osc_control_set(root->device->handle, -+ 0); -+ -+ if (status == AE_NOT_EXIST) { -+ printk(KERN_INFO "Unable to assume PCIe control: Disabling ASPM\n"); -+ pcie_no_aspm(); -+ } -+ - pci_acpi_add_bus_pm_notifier(device, root->bus); - if (device->wakeup.flags.run_wake) - device_set_run_wake(root->bus->bridge, true); |