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

[Alex Hung]

Some system supports hybrid graphics and its discrete VGA
does not have any connectors and therefore has no _DOD method.

BugLink: http://bugs.launchpad.net/bugs/1634607

Signed-off-by: Alex Hung <alex.hung at canonical.com>
Reviewed-by: Aaron Lu <aaron.lu at intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
(cherry picked from commit e34fbbac669de0b7fb7803929d0477f35f6e2833)
Signed-off-by: Alex Hung <alex.hung at 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"));
-- 
2.7.4