When we have CONFIG_PCIEASPM enabled it means OS can always support ASPM no matter user have disabled it through pcie_aspm=off or not. But currently we won't advertise ASPM support in _OSC negotiation if user disables it, which doesn't match the fact. This will also have side effects that other PCIe services like AER and hotplug will be disabled as ASPM support is required and we won't negotiate other services if ASPM support is absent. So this patch makes OS always advertising ASPM support if CONFIG_PCIEASPM=y. It intends no functional change to pcie_aspm=off as it will still mark aspm_disabled=1 and aspm_support_enabled=false, driver will check these status before configuring ASPM. Tested this patch with pcie_aspm=off: estuary:/$ dmesg | egrep -i "aspm|osc" [ 0.000000] PCIe ASPM is disabled [ 8.706961] acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI EDR HPX-Type3] [ 8.726032] acpi PNP0A08:00: _OSC: platform does not support [LTR] [ 8.742818] acpi PNP0A08:00: _OSC: OS now controls [PCIeHotplug PME AER PCIeCapability DPC] estuary:/sys/module/pcie_aspm/parameters$ cat policy [default] performance powersave powersupersave estuary:/sys/module/pcie_aspm/parameters$ echo powersave > policy bash: echo: write error: Operation not permitted Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx> Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> [https://lore.kernel.org/linux-pci/20220407154257.GA235990@bhelgaas/] Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx> --- drivers/acpi/pci_root.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 6f9e75d14808..17e78582e633 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -393,7 +393,7 @@ static u32 calculate_support(void) support |= OSC_PCI_HPX_TYPE_3_SUPPORT; if (pci_ext_cfg_avail()) support |= OSC_PCI_EXT_CONFIG_SUPPORT; - if (pcie_aspm_support_enabled()) + if (IS_ENABLED(CONFIG_PCIEASPM)) support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT; if (pci_msi_enabled()) support |= OSC_PCI_MSI_SUPPORT; -- 2.24.0
