On 2012-10-12 18:42, Tang Chen wrote:
> On 10/12/2012 06:36 PM, Jiang Liu wrote:
>> On 2012-10-12 18:31, Tang Chen 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>
>>> ---
>>> drivers/acpi/pci_root.c | 27 ++++++++++++++++++++++-----
>>> 1 files changed, 22 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>>> index 7d0fb03..3819bee 100644
>>> --- a/drivers/acpi/pci_root.c
>>> +++ b/drivers/acpi/pci_root.c
>>> @@ -128,9 +128,6 @@ 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.
>>> */
>>> int acpi_is_root_bridge(acpi_handle handle)
>>> {
>>> @@ -138,8 +135,28 @@ int acpi_is_root_bridge(acpi_handle handle)
>>> struct acpi_device *device;
>>>
>>> ret = acpi_bus_get_device(handle,&device);
>>> - if (ret)
>>> - return 0;
>>> + if (ret) {
>>> + /**
>>> + * If a device is not added to the system yet, there won't be
>>> + * an acpi_device struct for it. But it doesn't mean it is not
>>> + * a PCI root bridge. In this case we need to get HID and CID
>>> + * from ACPI namespace directly.
>>> + */
>>> + struct acpi_device_info *info;
>>> + acpi_status status;
>>> + 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_object_info_ids(info, root_device_ids);
>>> + if (ret)
>>> + return 0;
>>> + else
>>> + return 1;
>>> + }
>> I have sent a similar patch to Yinghai before. For simplicity, we could
>> use acpi_match_object_info_ids() instead of acpi_match_device_ids()
>> directly.
>
> Hum, I must have missed it. :)
> Using acpi_match_object_info_ids() directly seems good. I'm just worry
> about if it could cause any other problem. :)
>
> So now, is this bug fixed ? And we don't need these patches, right ?
>
> Thanks. :)
I think Yinghai has missed my patch too, so just suggest to use
acpi_match_object_info_ids() directly.
--Gerry
>
>> Thanks!
>> Gerry
>>
>>>
>>> ret = acpi_match_device_ids(device, root_device_ids);
>>> if (ret)
>>
>>
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>
>
> .
>
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