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| author |   Sinan Kaya <okaya@kernel.org> | 2018-08-10 04:32:12 +0000 |
|---|---|---|
| committer |   Bjorn Helgaas <bhelgaas@google.com> | 2018-09-17 16:32:24 -0500 |
| commit | c238252f86c1833fc0cbee3ce3b4c295d3ab24ef (patch) | |
| tree | 4d7b0116c0c4a86c6969564bf8ceceb02cfb15e0 /drivers/acpi | |
| parent | PCI/ACPI: Correct error message for ASPM disabling (diff) | |
| download | linux-dev-c238252f86c1833fc0cbee3ce3b4c295d3ab24ef.tar.xz linux-dev-c238252f86c1833fc0cbee3ce3b4c295d3ab24ef.zip | |
PCI/ACPI: Allow _OSC presence to be optional for PCI
The PCI Firmware Spec, r3.2, sec 4.5.1, says:
For a host bridge device that originates a PCI Express hierarchy, the
_OSC interface defined in this section is required. For a host bridge
device that originates a PCI/PCI-X bus hierarchy, inclusion of an _OSC
object is optional.
Allow PCI host bridges to bail out silently if _OSC is not found.
Reported-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sinan Kaya <okaya@kernel.org>
[bhelgaas: cite PCI Firmware spec, the authoritative source]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/pci_root.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index e465e720eab2..707aafc7c2aa 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -421,7 +421,8 @@ out: } EXPORT_SYMBOL(acpi_pci_osc_control_set); -static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) +static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, + bool is_pcie) { u32 support, control, requested; acpi_status status; @@ -455,10 +456,15 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) decode_osc_support(root, "OS supports", support); status = acpi_pci_osc_support(root, support); if (ACPI_FAILURE(status)) { + *no_aspm = 1; + + /* _OSC is optional for PCI host bridges */ + if ((status == AE_NOT_FOUND) && !is_pcie) + return; + dev_info(&device->dev, "_OSC failed (%s)%s\n", acpi_format_exception(status), pcie_aspm_support_enabled() ? "; disabling ASPM" : ""); - *no_aspm = 1; return; } @@ -534,6 +540,7 @@ static int acpi_pci_root_add(struct acpi_device *device, acpi_handle handle = device->handle; int no_aspm = 0; bool hotadd = system_state == SYSTEM_RUNNING; + bool is_pcie; root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL); if (!root) @@ -591,7 +598,8 @@ static int acpi_pci_root_add(struct acpi_device *device, root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle); - negotiate_os_control(root, &no_aspm); + is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0; + negotiate_os_control(root, &no_aspm, is_pcie); /* * TBD: Need PCI interface for enumeration/configuration of roots. |