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

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

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.

Thanks,
Aaron