Re: [PATCH] ACPI:video: skip evaluating _DOD when it does not exist

[Aaron Lu <aaron.lu@intel.com>]

On 06/06/2016 09:36 AM, Alex Hung wrote:
> On Fri, Jun 3, 2016 at 2:04 PM, Aaron Lu <aaron.lu@intel.com> wrote:
>> On Fri, May 27, 2016 at 03:47:06PM +0800, Alex Hung wrote:
>>> Some system supports hybrid graphics and its discrete VGA
>>> does not have any connectors and therefore has no _DOD method.
>>>
>>> Signed-off-by: Alex Hung <alex.hung@canonical.com>
>>> ---
>>>  drivers/acpi/acpi_video.c |    3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
>>> index 5fdac39..549cdbe 100644
>>> --- a/drivers/acpi/acpi_video.c
>>> +++ b/drivers/acpi/acpi_video.c
>>> @@ -1211,6 +1211,9 @@ static int acpi_video_device_enumerate(struct acpi_video_bus *video)
>>>       union acpi_object *dod = NULL;
>>>       union acpi_object *obj;
>>>
>>> +     if (!video->cap._DOD)
>>> +             return AE_NOT_EXIST;
>>> +
>>>       status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
>>>       if (!ACPI_SUCCESS(status)) {
>>>               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
>>
>> Is the patch supposed to avoid the above error message?
>> I'm OK with the patch though, it's just not clear to me the point since
>> the acpi_evaluate_object should probably also return AE_NOT_EXIST.
> 
> Yes it is to avoid the error message.  As _DOD is checked and it is
> known a specific video device does not have it, the error message can
> be confusing.

I see, thanks.

Reviewed-by: Aaron Lu <aaron.lu@intel.com>

Thanks,
Aaron