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Commit 6ef13824 authored by Lukas Wunner's avatar Lukas Wunner Committed by Bjorn Helgaas
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ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit 



We cache the PCI_EXP_SLTCAP_HPC bit in pci_dev->is_hotplug_bridge on device
probe, so there's no need to read it again when adding the ACPI hotplug
context.

Here's the call chain to prove that no ordering issue is introduced:

pci_scan_child_bus [drivers/pci/probe.c]
  pci_scan_slot
    pci_scan_single_device
      pci_scan_device
        pci_setup_device
          set_pcie_hotplug_bridge
            [is_hotplug_bridge bit is set here]
  pci_scan_bridge
    pci_add_new_bus
      pci_alloc_child_bus
        pcibios_add_bus  [arch/(x86|arm64|ia64)/...]
          acpi_pci_add_bus [drivers/pci/pci-acpi.c]
            acpiphp_enumerate_slots [drivers/pci/hotplug/acpiphp_glue.c]
              acpiphp_add_context
                device_is_managed_by_native_pciehp
                  [is_hotplug_bridge bit is queried here]

No functional change intended.

Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 718a0609

drivers/pci/hotplug/acpiphp_glue.c

+1 −4
Original line number Diff line number Diff line
@@ -225,14 +225,11 @@ static void acpiphp_post_dock_fixup(struct acpi_device *adev) 
/* Check whether the PCI device is managed by native PCIe hotplug driver */

static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev)

{

	u32 reg32;

	acpi_handle tmp;

	struct acpi_pci_root *root;



	/* Check whether the PCIe port supports native PCIe hotplug */

	if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &reg32))

		return false;

	if (!(reg32 & PCI_EXP_SLTCAP_HPC))

	if (!pdev->is_hotplug_bridge)

		return false;



	/*