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, 18 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index fd59f57d3829..8545b1d22811 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -434,7 +434,6 @@ static int acpi_pci_root_add(struct acpi_device *device)
         acpi_status status;
         int result;
         struct acpi_pci_root *root;
-        acpi_handle handle;
         struct acpi_pci_driver *driver;
         u32 flags, base_flags;
         bool is_osc_granted = false;
@@ -489,16 +488,6 @@ static int acpi_pci_root_add(struct acpi_device *device)
                acpi_device_name(device), acpi_device_bid(device),
                root->segment, &root->secondary);
 
-        /*
-         * PCI Routing Table
-         * -----------------
-         * Evaluate and parse _PRT, if exists.
-         */
-        status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
-        if (ACPI_SUCCESS(status))
-                result = acpi_pci_irq_add_prt(device->handle, root->segment,
-                                              root->secondary.start);
-
         root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);
 
         /*
@@ -623,7 +612,6 @@ out_del_root:
         list_del(&root->node);
         mutex_unlock(&acpi_pci_root_lock);
 
-        acpi_pci_irq_del_prt(root->segment, root->secondary.start);
 end:
         kfree(root);
         return result;
@@ -631,8 +619,6 @@ end:
 
 static int acpi_pci_root_remove(struct acpi_device *device, int type)
 {
-        acpi_status status;
-        acpi_handle handle;
         struct acpi_pci_root *root = acpi_driver_data(device);
         struct acpi_pci_driver *driver;
 
@@ -647,10 +633,6 @@ static int acpi_pci_root_remove(struct acpi_device *device, int type)
         device_set_run_wake(root->bus->bridge, false);
         pci_acpi_remove_bus_pm_notifier(device);
 
-        status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
-        if (ACPI_SUCCESS(status))
-                acpi_pci_irq_del_prt(root->segment, root->secondary.start);
-
         pci_remove_root_bus(root->bus);
 
         mutex_lock(&acpi_pci_root_lock);