drm/amd/display: fix graphics hang in multi-display mst case

[what]
Graphics hang observed with 3 displays connected to DP2.0 mst dock.

[why]
There's a mismatch in dml and dc between the assignments of hpo link
encoders.

[how]
Add a new array in dml that tracks the current mapping of HPO stream
encoders to HPO link encoders in dc.

Reviewed-by: Sung joon Kim <sungjoon.kim@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Gabe Teeger <Gabe.Teeger@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Gabe Teeger

drivers/gpu/drm/amd/display/dc/dml2/dml2_internal_types.h

@@ -101,7 +101,7 @@ struct dml2_wrapper_scratch {
 	struct dml2_dml_to_dc_pipe_mapping dml_to_dc_pipe_mapping;
 	bool enable_flexible_pipe_mapping;
 	bool plane_duplicate_exists;
-	unsigned int dp2_mst_stream_count;
+	int hpo_stream_to_link_encoder_mapping[MAX_HPO_DP2_ENCODERS];
 };
 
 struct dml2_helper_det_policy_scratch {

drivers/gpu/drm/amd/display/dc/dml2/dml2_translation_helper.c

@@ -733,8 +733,7 @@ static void populate_dml_timing_cfg_from_stream_state(struct dml_timing_cfg_st *
 }
 
 static void populate_dml_output_cfg_from_stream_state(struct dml_output_cfg_st *out, unsigned int location,
-				const struct dc_stream_state *in, const struct pipe_ctx *pipe,
-				unsigned int dp2_mst_stream_count)
+				const struct dc_stream_state *in, const struct pipe_ctx *pipe, struct dml2_context *dml2)
 {
 	unsigned int output_bpc;
 
@@ -747,8 +746,8 @@ static void populate_dml_output_cfg_from_stream_state(struct dml_output_cfg_st *
 	case SIGNAL_TYPE_DISPLAY_PORT_MST:
 	case SIGNAL_TYPE_DISPLAY_PORT:
 		out->OutputEncoder[location] = dml_dp;
-		if (is_dp2p0_output_encoder(pipe, dp2_mst_stream_count))
-			out->OutputEncoder[location] = dml_dp2p0;
+		if (dml2->v20.scratch.hpo_stream_to_link_encoder_mapping[location] != -1)
+			out->OutputEncoder[dml2->v20.scratch.hpo_stream_to_link_encoder_mapping[location]] = dml_dp2p0;
 		break;
 	case SIGNAL_TYPE_EDP:
 		out->OutputEncoder[location] = dml_edp;
@@ -1199,36 +1198,6 @@ static void dml2_populate_pipe_to_plane_index_mapping(struct dml2_context *dml2,
 	}
 }
 
-static unsigned int calculate_dp2_mst_stream_count(struct dc_state *context)
-{
-	int i, j;
-	unsigned int dp2_mst_stream_count = 0;
-
-	for (i = 0; i < context->stream_count; i++) {
-		struct dc_stream_state *stream = context->streams[i];
-
-		if (!stream || stream->signal != SIGNAL_TYPE_DISPLAY_PORT_MST)
-			continue;
-
-		for (j = 0; j < MAX_PIPES; j++) {
-			struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[j];
-
-			if (!pipe_ctx || !pipe_ctx->stream)
-				continue;
-
-			if (stream != pipe_ctx->stream)
-				continue;
-
-			if (pipe_ctx->stream_res.hpo_dp_stream_enc && pipe_ctx->link_res.hpo_dp_link_enc) {
-				dp2_mst_stream_count++;
-				break;
-			}
-		}
-	}
-
-	return dp2_mst_stream_count;
-}
-
 static void populate_dml_writeback_cfg_from_stream_state(struct dml_writeback_cfg_st *out,
 		unsigned int location, const struct dc_stream_state *in)
 {
@@ -1269,6 +1238,30 @@ static void populate_dml_writeback_cfg_from_stream_state(struct dml_writeback_cf
 		}
 	}
 }
+
+static void dml2_map_hpo_stream_encoder_to_hpo_link_encoder_index(struct dml2_context *dml2, struct dc_state *context)
+{
+	int i;
+	struct pipe_ctx *current_pipe_context;
+
+	/* Scratch gets reset to zero in dml, but link encoder instance can be zero, so reset to -1 */
+	for (i = 0; i < MAX_HPO_DP2_ENCODERS; i++) {
+		dml2->v20.scratch.hpo_stream_to_link_encoder_mapping[i] = -1;
+	}
+
+	/* If an HPO stream encoder is allocated to a pipe, get the instance of it's allocated HPO Link encoder */
+	for (i = 0; i < MAX_PIPES; i++) {
+		current_pipe_context = &context->res_ctx.pipe_ctx[i];
+		if (current_pipe_context->stream &&
+			current_pipe_context->stream_res.hpo_dp_stream_enc &&
+			current_pipe_context->link_res.hpo_dp_link_enc &&
+			dc_is_dp_signal(current_pipe_context->stream->signal)) {
+				dml2->v20.scratch.hpo_stream_to_link_encoder_mapping[current_pipe_context->stream_res.hpo_dp_stream_enc->inst] =
+					current_pipe_context->link_res.hpo_dp_link_enc->inst;
+			}
+	}
+}
+
 void map_dc_state_into_dml_display_cfg(struct dml2_context *dml2, struct dc_state *context, struct dml_display_cfg_st *dml_dispcfg)
 {
 	int i = 0, j = 0, k = 0;
@@ -1291,8 +1284,8 @@ void map_dc_state_into_dml_display_cfg(struct dml2_context *dml2, struct dc_stat
 	if (dml2->v20.dml_core_ctx.ip.hostvm_enable)
 		dml2->v20.dml_core_ctx.policy.AllowForPStateChangeOrStutterInVBlankFinal = dml_prefetch_support_uclk_fclk_and_stutter;
 
-	dml2->v20.scratch.dp2_mst_stream_count = calculate_dp2_mst_stream_count(context);
 	dml2_populate_pipe_to_plane_index_mapping(dml2, context);
+	dml2_map_hpo_stream_encoder_to_hpo_link_encoder_index(dml2, context);
 
 	for (i = 0; i < context->stream_count; i++) {
 		current_pipe_context = NULL;
@@ -1313,7 +1306,7 @@ void map_dc_state_into_dml_display_cfg(struct dml2_context *dml2, struct dc_stat
 		ASSERT(disp_cfg_stream_location >= 0 && disp_cfg_stream_location <= __DML2_WRAPPER_MAX_STREAMS_PLANES__);
 
 		populate_dml_timing_cfg_from_stream_state(&dml_dispcfg->timing, disp_cfg_stream_location, context->streams[i]);
-		populate_dml_output_cfg_from_stream_state(&dml_dispcfg->output, disp_cfg_stream_location, context->streams[i], current_pipe_context, dml2->v20.scratch.dp2_mst_stream_count);
+		populate_dml_output_cfg_from_stream_state(&dml_dispcfg->output, disp_cfg_stream_location, context->streams[i], current_pipe_context, dml2);
 		/*Call site for populate_dml_writeback_cfg_from_stream_state*/
 		populate_dml_writeback_cfg_from_stream_state(&dml_dispcfg->writeback,
 			disp_cfg_stream_location, context->streams[i]);
@@ -1378,7 +1371,7 @@ void map_dc_state_into_dml_display_cfg(struct dml2_context *dml2, struct dc_stat
 
 				if (j >= 1) {
 					populate_dml_timing_cfg_from_stream_state(&dml_dispcfg->timing, disp_cfg_plane_location, context->streams[i]);
-					populate_dml_output_cfg_from_stream_state(&dml_dispcfg->output, disp_cfg_plane_location, context->streams[i], current_pipe_context, dml2->v20.scratch.dp2_mst_stream_count);
+					populate_dml_output_cfg_from_stream_state(&dml_dispcfg->output, disp_cfg_plane_location, context->streams[i], current_pipe_context, dml2);
 					switch (context->streams[i]->debug.force_odm_combine_segments) {
 					case 2:
 						dml2->v20.dml_core_ctx.policy.ODMUse[disp_cfg_plane_location] = dml_odm_use_policy_combine_2to1;

drivers/gpu/drm/amd/display/dc/dml2/dml2_translation_helper.h

@@ -36,6 +36,6 @@ void dml2_translate_socbb_params(const struct dc *in_dc, struct soc_bounding_box
 void dml2_translate_soc_states(const struct dc *in_dc, struct soc_states_st *out, int num_states);
 void map_dc_state_into_dml_display_cfg(struct dml2_context *dml2, struct dc_state *context, struct dml_display_cfg_st *dml_dispcfg);
 void dml2_update_pipe_ctx_dchub_regs(struct _vcs_dpi_dml_display_rq_regs_st *rq_regs, struct _vcs_dpi_dml_display_dlg_regs_st *disp_dlg_regs, struct _vcs_dpi_dml_display_ttu_regs_st *disp_ttu_regs, struct pipe_ctx *out);
-bool is_dp2p0_output_encoder(const struct pipe_ctx *pipe, unsigned int dp2_mst_stream_count);
+bool is_dp2p0_output_encoder(const struct pipe_ctx *pipe);
 
 #endif //__DML2_TRANSLATION_HELPER_H__

drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c

@@ -153,22 +153,14 @@ unsigned int dml2_util_get_maximum_odm_combine_for_output(bool force_odm_4to1, e
 	}
 }
 
-bool is_dp2p0_output_encoder(const struct pipe_ctx *pipe_ctx, unsigned int dp2_mst_stream_count)
+bool is_dp2p0_output_encoder(const struct pipe_ctx *pipe_ctx)
 {
 	if (pipe_ctx == NULL || pipe_ctx->stream == NULL)
 		return false;
 
 	/* If this assert is hit then we have a link encoder dynamic management issue */
 	ASSERT(pipe_ctx->stream_res.hpo_dp_stream_enc ? pipe_ctx->link_res.hpo_dp_link_enc != NULL : true);
 
-	/* Count MST hubs once by treating only 1st remote sink in topology as an encoder */
-	if (pipe_ctx->stream->link && pipe_ctx->stream->link->remote_sinks[0] && dp2_mst_stream_count > 1) {
-		return (pipe_ctx->stream_res.hpo_dp_stream_enc &&
-			pipe_ctx->link_res.hpo_dp_link_enc &&
-			dc_is_dp_signal(pipe_ctx->stream->signal) &&
-			(pipe_ctx->stream->link->remote_sinks[0]->sink_id == pipe_ctx->stream->sink->sink_id));
-	}
-
 	return (pipe_ctx->stream_res.hpo_dp_stream_enc &&
 		pipe_ctx->link_res.hpo_dp_link_enc &&
 		dc_is_dp_signal(pipe_ctx->stream->signal));
@@ -181,7 +173,7 @@ bool is_dtbclk_required(const struct dc *dc, struct dc_state *context)
 	for (i = 0; i < dc->res_pool->pipe_count; i++) {
 		if (!context->res_ctx.pipe_ctx[i].stream)
 			continue;
-		if (is_dp2p0_output_encoder(&context->res_ctx.pipe_ctx[i], context->bw_ctx.dml2->v20.scratch.dp2_mst_stream_count))
+		if (is_dp2p0_output_encoder(&context->res_ctx.pipe_ctx[i]))
 			return true;
 	}
 	return false;