From: Yongqiang Sun <yongqiang.sun@amd.com>
Date: Mon, 5 Mar 2018 10:28:34 -0500
Subject: drm/amd/display: Fixed dim around 1sec when resume from S3 (v2)
Git-commit: 14d6f644368de1a890b747547f36cef0423fbec8
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

root cause:
DMCU try to perform a smoothness brightness change.Incorrect initial
brightness level causes the 1 sec dim.
Change:
Cache brightness level in stream, and clear it when edp backlight on.
If brightness level in stream is 0, set brightness with ramp value is 0.
DMCU will set the brightness without smoothness transition.

v2: squash in null pointer fix (Harry)

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@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               |    7 +++++++
 drivers/gpu/drm/amd/display/dc/dc_stream.h                  |    1 +
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c |    4 +++-
 3 files changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1960,6 +1960,13 @@ bool dc_link_set_backlight_level(const s
 		(abm->funcs->set_backlight_level == NULL))
 		return false;
 
+	if (stream) {
+		if (stream->bl_pwm_level == 0)
+			frame_ramp = 0;
+
+		((struct dc_stream_state *)stream)->bl_pwm_level = level;
+	}
+
 	use_smooth_brightness = dmcu->funcs->is_dmcu_initialized(dmcu);
 
 	DC_LOG_BACKLIGHT("New Backlight level: %d (0x%X)\n", level, level);
--- a/drivers/gpu/drm/amd/display/dc/dc_stream.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_stream.h
@@ -78,6 +78,7 @@ struct dc_stream_state {
 
 	/* DMCU info */
 	unsigned int abm_level;
+	unsigned int bl_pwm_level;
 
 	/* from core_stream struct */
 	struct dc_context *ctx;
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1006,8 +1006,10 @@ void dce110_unblank_stream(struct pipe_c
 	if (dc_is_dp_signal(pipe_ctx->stream->signal))
 		pipe_ctx->stream_res.stream_enc->funcs->dp_unblank(pipe_ctx->stream_res.stream_enc, &params);
 
-	if (link->local_sink && link->local_sink->sink_signal == SIGNAL_TYPE_EDP)
+	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;
+	}
 }
 void dce110_blank_stream(struct pipe_ctx *pipe_ctx)
 {