PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers

Previously, we cached _PRT (PCI routing table, ACPI 5.0 sec 6.2.12)
contents and associated each _PRT entry with a PCI bus number.  The bus
number association means dependencies on PCI device enumeration and bus
number assignment, as well as on the PCI/ACPI binding process.

After 4f535093cf ("PCI: Put pci_dev in device tree as early as possible"),
these dependencies caused the IRQ issues reported by Peter:

    pci 0000:00:1e.0: PCI bridge to [bus 09] (subtractive decode)
    pci 0000:00:1e.0: can't derive routing for PCI INT A
    snd_ctxfi 0000:09:02.0: PCI INT A: no GSI - using ISA IRQ 5
    irq 18: nobody cared (try booting with the "irqpoll" option)

This patch removes _PRT caching.  Instead, we evaluate _PRT as needed
in the pci_enable_device() path.  This also removes the dependency on
PCI bus numbers: we can simply look at the _PRT associated with each
bridge as we walk upstream toward the root.

[bhelgaas: changelog]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=53561
Reported-and-tested-by: Peter Hurley <peter@hurleysoftware.com>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 0 insertions, 24 deletions

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 42736e213f25..9ba9df5f6161 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -325,25 +325,6 @@ static void pci_acpi_setup(struct device *dev)
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	acpi_handle handle = ACPI_HANDLE(dev);
 	struct acpi_device *adev;
-	acpi_status status;
-	acpi_handle dummy;
-
-	/*
-	 * Evaluate and parse _PRT, if exists.  This code allows parsing of
-	 * _PRT objects within the scope of non-bridge devices.  Note that
-	 * _PRTs within the scope of a PCI bridge assume the bridge's
-	 * subordinate bus number.
-	 *
-	 * TBD: Can _PRTs exist within the scope of non-bridge PCI devices?
-	 */
-	status = acpi_get_handle(handle, METHOD_NAME__PRT, &dummy);
-	if (ACPI_SUCCESS(status)) {
-		unsigned char bus;
-
-		bus = pci_dev->subordinate ?
-			pci_dev->subordinate->number : pci_dev->bus->number;
-		acpi_pci_irq_add_prt(handle, pci_domain_nr(pci_dev->bus), bus);
-	}
 
 	acpi_power_resource_register_device(dev, handle);
 	if (acpi_bus_get_device(handle, &adev) || !adev->wakeup.flags.valid)
@@ -359,7 +340,6 @@ static void pci_acpi_setup(struct device *dev)
 
 static void pci_acpi_cleanup(struct device *dev)
 {
-	struct pci_dev *pci_dev = to_pci_dev(dev);
 	acpi_handle handle = ACPI_HANDLE(dev);
 	struct acpi_device *adev;
 
@@ -369,10 +349,6 @@ static void pci_acpi_cleanup(struct device *dev)
 		pci_acpi_remove_pm_notifier(adev);
 	}
 	acpi_power_resource_unregister_device(dev, handle);
-
-	if (pci_dev->subordinate)
-		acpi_pci_irq_del_prt(pci_domain_nr(pci_dev->bus),
-				     pci_dev->subordinate->number);
 }
 
 static struct acpi_bus_type acpi_pci_bus = {