[PATCH AUTOSEL 5.3 62/87] drm/amd/display: fix trigger not generated for freesync

[Sasha Levin]

From: Yogesh Mohan Marimuthu <yogesh.mohanmarimuthu at amd.com>

[ Upstream commit 1e7f100ce8c0640634b794604880d9204480c9f1 ]

[Why]
In newer hardware MANUAL_FLOW_CONTROL is not a trigger bit. Due to this
front porch is fixed and in these hardware freesync does not work.

[How]
Change the programming to generate a pulse so that the event will be
triggered, front porch will be cut short and freesync will work.

Signed-off-by: Yogesh Mohan Marimuthu <yogesh.mohanmarimuthu at amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
index a546c2bc9129c..e365f2dd7f9a9 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
@@ -824,6 +824,9 @@ void optc1_program_manual_trigger(struct timing_generator *optc)
 
 	REG_SET(OTG_MANUAL_FLOW_CONTROL, 0,
 			MANUAL_FLOW_CONTROL, 1);
+
+	REG_SET(OTG_MANUAL_FLOW_CONTROL, 0,
+			MANUAL_FLOW_CONTROL, 0);
 }
 
 
-- 
2.20.1