From: Alex Hung <alex.hung@canonical.com>
Date: Fri, 27 May 2016 07:47:06 +0000 (+0800)
Subject: ACPI / video: skip evaluating _DOD when it does not exist
X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~20^2~100
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=962c66c74184b1c7927f5906c9848e605fe8b236;p=firefly-linux-kernel-4.4.55.git

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

commit e34fbbac669de0b7fb7803929d0477f35f6e2833 upstream.

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>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 5fdac394207a..549cdbed7b0e 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"));