[PATCH AUTOSEL 6.7 68/88] drm/amd/display: Fix lightup regression with DP2 single display configs

[Sasha Levin]

From: Michael Strauss <michael.strauss@xxxxxxx>

[ Upstream commit 5a82b8d6c05f9b30828ede1b103b9ee5cb5c912e ]

[WHY]
Previous fix for multiple displays downstream of DP2 MST hub caused regression

[HOW]
Match sink IDs instead of sink struct addresses

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
Reviewed-by: Charlene Liu <charlene.liu@xxxxxxx>
Acked-by: Wayne Lin <wayne.lin@xxxxxxx>
Signed-off-by: Michael Strauss <michael.strauss@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c b/drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c
index 2498b8341199..d6a68484153c 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml2_utils.c
@@ -157,6 +157,14 @@ bool is_dp2p0_output_encoder(const struct pipe_ctx *pipe_ctx)
 {
 	/* 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]) {
+		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));
-- 
2.43.0