[PATCH 24/25] drm/amd/display: Cache streams targeting link when performing LT automation

[IVAN.LIPSKI at amd.com]

From: Michael Strauss <michael.strauss at amd.com>

[WHY]
Last LT automation update can cause crash by referencing current_state and
calling into dc_update_planes_and_stream which may clobber current_state.

[HOW]
Cache relevant stream pointers and iterate through them instead of relying
on the current_state.

Reviewed-by: Wenjing Liu <wenjing.liu at amd.com>
Signed-off-by: Michael Strauss <michael.strauss at amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski at amd.com>
---
 .../display/dc/link/accessories/link_dp_cts.c   | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c b/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
index 2956c2b3ad1a..9e33bf937a69 100644
--- a/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
+++ b/drivers/gpu/drm/amd/display/dc/link/accessories/link_dp_cts.c
@@ -76,6 +76,8 @@ static void dp_retrain_link_dp_test(struct dc_link *link,
 	uint8_t count;
 	int i;
 	struct audio_output audio_output[MAX_PIPES];
+	struct dc_stream_state *streams_on_link[MAX_PIPES];
+	int num_streams_on_link = 0;
 
 	needs_divider_update = (link->dc->link_srv->dp_get_encoding_format(link_setting) !=
 	link->dc->link_srv->dp_get_encoding_format((const struct dc_link_settings *) &link->cur_link_settings));
@@ -138,12 +140,19 @@ static void dp_retrain_link_dp_test(struct dc_link *link,
 		pipes[i]->stream_res.tg->funcs->enable_crtc(pipes[i]->stream_res.tg);
 
 	// Set DPMS on with stream update
-	for (i = 0; i < state->stream_count; i++)
-		if (state->streams[i] && state->streams[i]->link && state->streams[i]->link == link) {
-			stream_update.stream = state->streams[i];
+	// Cache all streams on current link since dc_update_planes_and_stream might kill current_state
+	for (i = 0; i < MAX_PIPES; i++) {
+		if (state->streams[i] && state->streams[i]->link && state->streams[i]->link == link)
+			streams_on_link[num_streams_on_link++] = state->streams[i];
+	}
+
+	for (i = 0; i < num_streams_on_link; i++) {
+		if (streams_on_link[i] && streams_on_link[i]->link && streams_on_link[i]->link == link) {
+			stream_update.stream = streams_on_link[i];
 			stream_update.dpms_off = &dpms_off;
-			dc_update_planes_and_stream(state->clk_mgr->ctx->dc, NULL, 0, state->streams[i], &stream_update);
+			dc_update_planes_and_stream(state->clk_mgr->ctx->dc, NULL, 0, streams_on_link[i], &stream_update);
 		}
+	}
 }
 
 static void dp_test_send_link_training(struct dc_link *link)
-- 
2.43.0