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ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit

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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: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lukas Wunner 2016-10-28 10:52:06 +02:00 committed by Bjorn Helgaas
parent 718a0609ae
commit 6ef13824e0
1 changed files with 1 additions and 4 deletions
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5
drivers/pci/hotplug/acpiphp_glue.c
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@ -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;
/*