On Fri, Oct 12, 2012 at 5:34 AM, Tang Chen <tangchen@xxxxxxxxxxxxxx> wrote:
> When the kernel is being initialized, and some hardwares are not added
> to system, there won't be acpi_device structs for these devices. But
> acpi_is_root_bridge() depends on acpi_device struct. As a result, all
> the not-added root bridge will not be judged as a root bridge in
> find_root_bridges(). And further more, no handle_hotplug_event_root()
> notifier will be installed for them.
>
> This patch introduces a new api to find all root bridges in system by
> getting HID directly from ACPI namespace, not depending on acpi_device
> struct.
>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Signed-off-by: Liu Jiang <jiang.liu@xxxxxxxxxx>
> ---
> drivers/acpi/pci_root.c | 19 +++++++++++--------
> 1 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 6151d83..582eb11 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -129,20 +129,23 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
> * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
> * @handle - the ACPI CA node in question.
> *
> - * Note: we could make this API take a struct acpi_device * instead, but
> - * for now, it's more convenient to operate on an acpi_handle.
> + * Note: If a device is not added to the system yet, there won't be an
> + * acpi_device struct for it. So do not get HID and CID from acpi_device,
> + * get them from ACPI namespace directly.
> */
> int acpi_is_root_bridge(acpi_handle handle)
> {
> - int ret;
> - struct acpi_device *device;
> + struct acpi_device_info *info;
> + acpi_status status;
>
> - ret = acpi_bus_get_device(handle, &device);
> - if (ret)
> + status = acpi_get_object_info(handle, &info);
> + if (ACPI_FAILURE(status)) {
> + printk(KERN_ERR PREFIX "%s: Error reading"
> + "device info\n", __func__);
> return 0;
> + }
>
> - ret = acpi_match_device_ids(device, root_device_ids);
> - if (ret)
> + if (acpi_match_object_info_ids(info, root_device_ids))
> return 0;
> else
> return 1;
there are some other users for acpi_is_root_bridge.
drivers/acpi/pci_root.c: while (!acpi_is_root_bridge(phandle)) {
drivers/pci/hotplug/acpi_pcihp.c: if (acpi_is_root_bridge(handle))
drivers/pci/hotplug/acpi_pcihp.c: if (acpi_is_root_bridge(handle))
and they are ok to have acpi_device ready.
so we could have another separated static version for those not added ones?
Thanks
Yinghai
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