From: Roman Li <Roman.Li@amd.com>
Date: Thu, 29 Mar 2018 10:56:17 -0400
Subject: drm/amd/display: fix brightness level after resume from suspend
Git-commit: c3d7bad88e3b35b981eecc1645ddbb3f13a8b54f
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Adding missing call to cache current backlight values.
Otherwise the brightness resets to default value on resume.

Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@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               |   13 ++++++++++++
 drivers/gpu/drm/amd/display/dc/dc_link.h                    |    2 +
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c |    4 ++-
 3 files changed, 18 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
@@ -1997,6 +1997,19 @@ bool dc_link_set_backlight_level(const s
 	return true;
 }
 
+bool dc_link_set_abm_disable(const struct dc_link *link)
+{
+	struct dc  *core_dc = link->ctx->dc;
+	struct abm *abm = core_dc->res_pool->abm;
+
+	if ((abm == NULL) || (abm->funcs->set_backlight_level == NULL))
+		return false;
+
+	abm->funcs->set_abm_immediate_disable(abm);
+
+	return true;
+}
+
 bool dc_link_set_psr_enable(const struct dc_link *link, bool enable, bool wait)
 {
 	struct dc  *core_dc = link->ctx->dc;
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -132,6 +132,8 @@ static inline struct dc_link *dc_get_lin
 bool dc_link_set_backlight_level(const struct dc_link *dc_link, uint32_t level,
 		uint32_t frame_ramp, const struct dc_stream_state *stream);
 
+bool dc_link_set_abm_disable(const struct dc_link *dc_link);
+
 bool dc_link_set_psr_enable(const struct dc_link *dc_link, bool enable, bool wait);
 
 bool dc_link_get_psr_state(const struct dc_link *dc_link, uint32_t *psr_state);
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1016,8 +1016,10 @@ void dce110_blank_stream(struct pipe_ctx
 	struct dc_stream_state *stream = pipe_ctx->stream;
 	struct dc_link *link = stream->sink->link;
 
-	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, false);
+		dc_link_set_abm_disable(link);
+	}
 
 	if (dc_is_dp_signal(pipe_ctx->stream->signal))
 		pipe_ctx->stream_res.stream_enc->funcs->dp_blank(pipe_ctx->stream_res.stream_enc);