On Tuesday 14 July 2009 02:53:33 pm Alex Chiang wrote:
> We cannot simply call acpi_get_pci_dev() on any random ACPI handle
> and hope that it works, because a PCI root bridge may not have
> an associated struct pci_dev.
>
> This is allowed per the PCI specification, and is referred to as a
> non-materialized bridge.
>
> So, depending on the type of PCI bridge that the handle points to,
> use the appropriate interface to return the struct pci_bus correctly.
>
> Signed-off-by: Alex Chiang <achiang@xxxxxx>
> ---
>
> drivers/pci/hotplug/acpiphp_glue.c | 27 ++++++++++++++++-----------
> 1 files changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
> index 0cb0f83..fa4658b 100644
> --- a/drivers/pci/hotplug/acpiphp_glue.c
> +++ b/drivers/pci/hotplug/acpiphp_glue.c
> @@ -62,6 +62,21 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus);
> static void acpiphp_set_hpp_values(acpi_handle handle, struct pci_bus *bus);
> static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
>
> +static struct pci_bus *pci_bus_from_handle(acpi_handle handle)
> +{
> + struct pci_bus *pbus;
> +
> + if (acpi_is_root_bridge(handle)) {
> + struct acpi_pci_root *root = acpi_pci_find_root(handle);
> + pbus = root->bus;
> + } else {
> + struct pci_dev *pdev = acpi_get_pci_dev(handle);
> + pbus = pdev->subordinate;
> + pci_dev_put(pdev);
> + }
> + return pbus;
I worry that acpi_is_root_bridge() merely checks the device IDs of
"handle", which isn't quite the same as checking whether the pci_root
driver has claimed "handle".
Are you confident that it's safe to move the pci_dev_put(), so it is
released before configuring the bridge?
What do you think about something like this (even though the get/put
is still a little clunky):
struct pci_dev *dev = NULL;
root = acpi_pci_find_root(handle);
if (root)
bus = root->bus;
else {
dev = acpi_get_pci_dev(handle);
if (dev)
bus = pdev->subordinate;
else {
err("cannot get PCI domain and bus number for bridge\n");
return -EINVAL;
}
}
pci_bus_size_bridges(bus);
...
if (dev)
pci_dev_put(dev);
return 0;
> +}
> +
> /* callback routine to check for the existence of a pci dock device */
> static acpi_status
> is_pci_dock_device(acpi_handle handle, u32 lvl, void *context, void **rv)
> @@ -1387,16 +1402,7 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus)
> /* Program resources in newly inserted bridge */
> static int acpiphp_configure_bridge (acpi_handle handle)
> {
> - struct pci_dev *dev;
> - struct pci_bus *bus;
> -
> - dev = acpi_get_pci_dev(handle);
> - if (!dev) {
> - err("cannot get PCI domain and bus number for bridge\n");
> - return -EINVAL;
> - }
> -
> - bus = dev->bus;
> + struct pci_bus *bus = pci_bus_from_handle(handle);
>
> pci_bus_size_bridges(bus);
> pci_bus_assign_resources(bus);
> @@ -1404,7 +1410,6 @@ static int acpiphp_configure_bridge (acpi_handle handle)
> acpiphp_set_hpp_values(handle, bus);
> pci_enable_bridges(bus);
> acpiphp_configure_ioapics(handle);
> - pci_dev_put(dev);
> return 0;
> }
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