On Mon, Apr 25, 2022 at 03:06:34PM +0800, Yicong Yang wrote: > 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)) Is there any way firmware could tell the difference between "CONFIG_PCIEASPM not set" and "CONFIG_PCIEASPM=y and booted with 'pcie_aspm=off'"? If not, why would we even check whether CONFIG_PCIEASPM is set? > support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT; > if (pci_msi_enabled()) > support |= OSC_PCI_MSI_SUPPORT; > -- > 2.24.0 >
