From: David Galiffi <David.Galiffi@amd.com>
Date: Thu, 11 Jun 2020 21:36:14 +0000 (-0400)
Subject: drm/amd/display: Compare v_front_porch when checking if streams are synchronizable
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8582aea20bc5de1fc4f2029e6cde604b2c755c0a;p=linux.git

drm/amd/display: Compare v_front_porch when checking if streams are synchronizable

[Why]
If the front porch of the two timings differ, then there may not be
enough time while both streams are in vertical blank to perform a memory
clock change. This can hang the system.

[How]
Check the each streams timing.v_front_porch when determining if the two
streams are synchronizable.

Signed-off-by: David Galiffi <David.Galiffi@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index 3d0003c69373f..1000dc6daf722 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -399,6 +399,10 @@ bool resource_are_streams_timing_synchronizable(
 				!= stream2->timing.v_addressable)
 		return false;
 
+	if (stream1->timing.v_front_porch
+				!= stream2->timing.v_front_porch)
+		return false;
+
 	if (stream1->timing.pix_clk_100hz
 				!= stream2->timing.pix_clk_100hz)
 		return false;