From: Yongqiang Sun <yongqiang.sun@amd.com>
Date: Tue, 27 Mar 2018 10:05:10 -0400
Subject: drm/amd/display: Change disable backlight ramp change threshold from
 0 to maximum value.
Git-commit: 5282cbe32ea5b8008f86a743922f018287113e2c
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Instead of user set brightness with range of percentage,
HLK test set brightness level with range of normal, this will result in
HLK test case set brightness from 0 to 255, DC set brightness with ramp is 0,
and disabled ramp change which will fail the HLK test.
Fix:
In case of unblank stream and turn on edp, change brightness level in
stream to 0xFFFFFFFF(actural maximum level is 0xFF), use that value as
a flag to recogonize this the case of resume from S3.

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c               |    2 +-
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c |    2 +-
 drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h           |    2 ++
 3 files changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1982,7 +1982,7 @@ bool dc_link_set_backlight_level(const s
 		return false;
 
 	if (stream) {
-		if (stream->bl_pwm_level == 0)
+		if (stream->bl_pwm_level == EDP_BACKLIGHT_RAMP_DISABLE_LEVEL)
 			frame_ramp = 0;
 
 		((struct dc_stream_state *)stream)->bl_pwm_level = level;
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1039,7 +1039,7 @@ void dce110_unblank_stream(struct pipe_c
 
 	if (link->local_sink && link->local_sink->sink_signal == SIGNAL_TYPE_EDP) {
 		link->dc->hwss.edp_backlight_control(link, true);
-		stream->bl_pwm_level = 0;
+		stream->bl_pwm_level = EDP_BACKLIGHT_RAMP_DISABLE_LEVEL;
 	}
 }
 void dce110_blank_stream(struct pipe_ctx *pipe_ctx)
--- a/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h
@@ -32,6 +32,8 @@
 #include "inc/hw/link_encoder.h"
 #include "core_status.h"
 
+#define EDP_BACKLIGHT_RAMP_DISABLE_LEVEL 0xFFFFFFFF
+
 enum pipe_gating_control {
 	PIPE_GATING_CONTROL_DISABLE = 0,
 	PIPE_GATING_CONTROL_ENABLE,