On 8/15/19 3:19 PM, Bjorn Helgaas wrote:
On Fri, Jul 26, 2019 at 02:43:13PM -0700, 
sathyanarayanan.kuppusw...@linux.intel.com wrote:
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppusw...@linux.intel.com>

As per PCI firmware specification r3.2 Downstream Port Containment
Related Enhancements ECN, sec 4.5.1, table 4-4, if OS supports EDR,
it should expose its support to BIOS by setting bit 7 of _OSC Support
Field.

Cc: Bjorn Helgaas <bhelg...@google.com>
Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
Cc: Len Brown <l...@kernel.org>
Signed-off-by: Kuppuswamy Sathyanarayanan 
<sathyanarayanan.kuppusw...@linux.intel.com>
---
  drivers/acpi/pci_root.c | 3 +++
  include/linux/acpi.h    | 1 +
  2 files changed, 4 insertions(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 73b08f40b0da..988d09d788b6 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -132,6 +132,7 @@ static struct pci_osc_bit_struct pci_osc_support_bit[] = {
        { OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
        { OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
        { OSC_PCI_MSI_SUPPORT, "MSI" },
+       { OSC_PCI_EDR_SUPPORT, "EDR" },
        { OSC_PCI_HPX_TYPE_3_SUPPORT, "HPX-Type3" },
  };
@@ -442,6 +443,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
                support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
        if (pci_msi_enabled())
                support |= OSC_PCI_MSI_SUPPORT;
+       if (IS_ENABLED(CONFIG_PCIE_EDR))
+               support |= OSC_PCI_EDR_SUPPORT;
Do we really support it here?  This is patch [3/9] and it looks like
patch [6/9] might be where EDR support really gets added.  It's good
to split changes into small pieces, but only if each piece is
logically self-contained.
I will move this patch to the end of this series.

        decode_osc_support(root, "OS supports", support);
        status = acpi_pci_osc_support(root, support);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 8959ed322e15..b6b43da85d26 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -515,6 +515,7 @@ extern bool osc_pc_lpi_support_confirmed;
  #define OSC_PCI_CLOCK_PM_SUPPORT              0x00000004
  #define OSC_PCI_SEGMENT_GROUPS_SUPPORT                0x00000008
  #define OSC_PCI_MSI_SUPPORT                   0x00000010
+#define OSC_PCI_EDR_SUPPORT                    0x00000080
  #define OSC_PCI_HPX_TYPE_3_SUPPORT            0x00000100
  #define OSC_PCI_SUPPORT_MASKS                 0x0000011f
You defined a new bit above but didn't update OSC_PCI_SUPPORT_MASKS to
include that bit.  This looks broken.

--
Sathyanarayanan Kuppuswamy
Linux kernel developer

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