[PATCH 22/28] drm/amd/display: Improve DisplayPort monitor interop

[Qingqing Zhuo]

From: Aric Cyr <aric.cyr at amd.com>

[Why]
DC is very fast at link training and stream enablement
which causes issues such as blackscreens for non-compliant
monitors.

[How]
After debugging with scaler vendors we implement the
minimum delays at the necessary locations to ensure
the monitor does not hang.  Delays are generic due to
lack of IEEE OUI information on the failing displays.

Also reverts commit b9976bd920a19d509de09b6dc727fcaae60fbb32.

Signed-off-by: Aric Cyr <aric.cyr at amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu at amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo at amd.com>
Acked-by: Tony Cheng <Tony.Cheng at amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c |  4 +++-
 .../gpu/drm/amd/display/dc/core/dc_link_dp.c  | 23 +++++++++++--------
 drivers/gpu/drm/amd/display/dc/dc.h           |  1 -
 .../display/dc/dce110/dce110_hw_sequencer.c   | 11 ++++++++-
 4 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index cbb4c24d748d..114ee29132fa 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -3309,9 +3309,11 @@ void core_link_disable_stream(struct pipe_ctx *pipe_ctx)
 			write_i2c_redriver_setting(pipe_ctx, false);
 		}
 	}
-	dc->hwss.disable_stream(pipe_ctx);
 
 	disable_link(pipe_ctx->stream->link, pipe_ctx->stream->signal);
+
+	dc->hwss.disable_stream(pipe_ctx);
+
 	if (pipe_ctx->stream->timing.flags.DSC) {
 		if (dc_is_dp_signal(pipe_ctx->stream->signal))
 			dp_set_dsc_enable(pipe_ctx, false);
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 6c03dcd6acb5..484a6849f3de 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -1102,6 +1102,10 @@ static inline enum link_training_result perform_link_training_int(
 	dpcd_pattern.v1_4.TRAINING_PATTERN_SET = DPCD_TRAINING_PATTERN_VIDEOIDLE;
 	dpcd_set_training_pattern(link, dpcd_pattern);
 
+	/* delay 5ms after notifying sink of idle pattern before switching output */
+	if (link->connector_signal != SIGNAL_TYPE_EDP)
+		msleep(5);
+
 	/* 4. mainlink output idle pattern*/
 	dp_set_hw_test_pattern(link, DP_TEST_PATTERN_VIDEO_MODE, NULL, 0);
 
@@ -1551,6 +1555,12 @@ bool perform_link_training_with_retries(
 	struct dc_link *link = stream->link;
 	enum dp_panel_mode panel_mode = dp_get_panel_mode(link);
 
+	/* We need to do this before the link training to ensure the idle pattern in SST
+	 * mode will be sent right after the link training
+	 */
+	link->link_enc->funcs->connect_dig_be_to_fe(link->link_enc,
+							pipe_ctx->stream_res.stream_enc->id, true);
+
 	for (j = 0; j < attempts; ++j) {
 
 		dp_enable_link_phy(
@@ -1559,21 +1569,14 @@ bool perform_link_training_with_retries(
 			pipe_ctx->clock_source->id,
 			link_setting);
 
-		if ((link && link->dc->debug.dppowerup_delay > 0) || stream->sink_patches.dppowerup_delay > 0) {
-			int delay_dp_power_up_in_ms =
-				(link->dc->debug.dppowerup_delay >= stream->sink_patches.dppowerup_delay) ?
-				link->dc->debug.dppowerup_delay : stream->sink_patches.dppowerup_delay;
+		if (stream->sink_patches.dppowerup_delay > 0) {
+			int delay_dp_power_up_in_ms = stream->sink_patches.dppowerup_delay;
+
 			msleep(delay_dp_power_up_in_ms);
 		}
 
 		dp_set_panel_mode(link, panel_mode);
 
-		/* We need to do this before the link training to ensure the idle pattern in SST
-		 * mode will be sent right after the link training
-		 */
-		link->link_enc->funcs->connect_dig_be_to_fe(link->link_enc,
-								pipe_ctx->stream_res.stream_enc->id, true);
-
 		if (link->aux_access_disabled) {
 			dc_link_dp_perform_link_training_skip_aux(link, link_setting);
 			return true;
diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h
index f9bdd9115edc..7da41d465a34 100644
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -498,7 +498,6 @@ struct dc_debug_options {
 	bool usbc_combo_phy_reset_wa;
 	bool disable_dsc;
 	bool enable_dram_clock_change_one_display_vactive;
-	unsigned int dppowerup_delay;
 };
 
 struct dc_debug_data {
diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
index 0ce430cf4dd0..49380ed3aeae 100644
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1069,8 +1069,17 @@ void dce110_blank_stream(struct pipe_ctx *pipe_ctx)
 		link->dc->hwss.set_abm_immediate_disable(pipe_ctx);
 	}
 
-	if (dc_is_dp_signal(pipe_ctx->stream->signal))
+	if (dc_is_dp_signal(pipe_ctx->stream->signal)) {
 		pipe_ctx->stream_res.stream_enc->funcs->dp_blank(pipe_ctx->stream_res.stream_enc);
+
+		/*
+		 * After output is idle pattern some sinks need time to recognize the stream
+		 * has changed or they enter protection state and hang.
+		 */
+		if (!dc_is_embedded_signal(pipe_ctx->stream->signal))
+			msleep(60);
+	}
+
 }
 
 
-- 
2.17.1