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Commit 4e5fad42 authored Mar 27, 2018 by Mika Westerberg Committed by Bjorn Helgaas Mar 30, 2018

PCI/DPC: Do not enable DPC if AER control is not allowed by the BIOS



Commit eed85ff4 ("PCI/DPC: Enable DPC only if AER is available") made
DPC control dependent whether AER is enabled in the OS.  However, it does
not take into account situations where BIOS has not given OS control of
AER:

  acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
  acpi PNP0A08:00: _OSC: platform does not support [AER]
  acpi PNP0A08:00: _OSC: OS now controls [PCIeHotplug PME PCIeCapability]

I think here it is better not to enable DPC even if the capability is
available because then it would be against what "Determination of DPC
Control" note in PCIe 4.0 sec 6.1.10 recommends.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>

parent f0553ba0

drivers/pci/pcie/portdrv_acpi.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -47,11 +47,11 @@ void pcie_port_acpi_setup(struct pci_dev port, int srv_mask)

	flags = root->osc_control_set;		flags = root->osc_control_set;

	*srv_mask = PCIE_PORT_SERVICE_DPC;		*srv_mask = 0;
	if (flags & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)		if (flags & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)
	*srv_mask \|= PCIE_PORT_SERVICE_HP;		*srv_mask \|= PCIE_PORT_SERVICE_HP;
	if (flags & OSC_PCI_EXPRESS_PME_CONTROL)		if (flags & OSC_PCI_EXPRESS_PME_CONTROL)
	*srv_mask \|= PCIE_PORT_SERVICE_PME;		*srv_mask \|= PCIE_PORT_SERVICE_PME;
	if (flags & OSC_PCI_EXPRESS_AER_CONTROL)		if (flags & OSC_PCI_EXPRESS_AER_CONTROL)
	*srv_mask \|= PCIE_PORT_SERVICE_AER;		*srv_mask \|= PCIE_PORT_SERVICE_AER \| PCIE_PORT_SERVICE_DPC;
	}		}

drivers/pci/pcie/portdrv_core.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -242,7 +242,7 @@ static int get_port_device_capability(struct pci_dev *dev)
	}		}

	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&		if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
	pci_aer_available())		pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
	services \|= PCIE_PORT_SERVICE_DPC;		services \|= PCIE_PORT_SERVICE_DPC;

	return services;		return services;