[PATCH v2 0/2] Improve _OSC control request granularity

[Aaron Sierra <asierra@xes-inc.com>]

These patches allow PCIe AER to function in a kernel without
CONFIG_PCIEASPM enabled. There is no explicit Kbuild dependency between
the two and there are, in my opinion, legitimate reasons for no implicit
dependency to exist either.

Previously with ASPM:

acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
acpi PNP0A03:00: _OSC: OS now controls [PME AER PCIeCapability LTR]

Previously without ASPM:

acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig Segments MSI]
acpi PNP0A03:00: _OSC: not requesting OS control; OS requires [ExtendedConfig ASPM ClockPM MSI]

Now with ASPM:

acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
acpi PNP0A03:00: _OSC: OS requested [PME AER PCIeCapability LTR]
acpi PNP0A03:00: _OSC: platform granted [PME AER PCIeCapability LTR]

Now without ASPM:

acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig Segments MSI]
acpi PNP0A03:00: _OSC: OS requested [AER PCIeCapability]
acpi PNP0A03:00: _OSC: platform granted [AER PCIeCapability]

This is v2 of the patchset, which includes these changes from v1:
  * Rebased from the mainline kernel (4.19-rc7) to Bjorn Helgaas's
    pci/aspm branch [1]
  * Factored moving the pcie_ports_disabled check to the top of
    negotiate_os_control into its own patch
  * Simplified new __osc_check_support function and renamed it to
    __osc_have_support
  * No longer messes with _OSC general availability test and related
    error message (i.e. _OSC failed ... disabling ASPM)

[1] https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git

Aaron Sierra (2):
  PCI/ACPI: Move _OSC test for native services to top
  PCI/ACPI: Improve _OSC control request granularity

 drivers/acpi/pci_root.c | 129 ++++++++++++++++++++++++++++++++++--------------
 1 file changed, 91 insertions(+), 38 deletions(-)

-- 
2.7.4