drm/amd/display: make enable link independent from verified link caps

[why]
Ideally link capability should be independent from the link
configuration that we decide to use in enable link. Otherwise if link
capability is changed after validation has completed, we could end up
enabling a link configuration with invalid configuration. This would
lead to over link bandwidth subscription or in the extreme case
causes us to enable HPO link to a DIO stream.

[how]
Add a new struct in pipe ctx called link config. This structure will
contain link configuration to enable a link. It will be populated
during map pool resources after we validate link bandwidth. Remove
the reference of verified link cap during enable link process and
use link config in pipe ctx instead.

Reviewed-by: George Shen <George.Shen@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 10 insertions, 17 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 dbdeda60e9e2..65269cd8cb78 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1969,7 +1969,8 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 	enum dc_status status;
 	bool skip_video_pattern;
 	struct dc_link *link = stream->link;
-	struct dc_link_settings link_settings = {0};
+	const struct dc_link_settings *link_settings =
+			&pipe_ctx->link_config.dp_link_settings;
 	bool fec_enable;
 	int i;
 	bool apply_seamless_boot_optimization = false;
@@ -1986,9 +1987,6 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 		}
 	}
 
-	/* get link settings for video mode timing */
-	decide_link_settings(stream, &link_settings);
-
 	/* Train with fallback when enabling DPIA link. Conventional links are
 	 * trained with fallback during sink detection.
 	 */
@@ -1999,7 +1997,7 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 	 * Temporary w/a to get DP2.0 link rates to work with SST.
 	 * TODO DP2.0 - Workaround: Remove w/a if and when the issue is resolved.
 	 */
-	if (dp_get_link_encoding_format(&link_settings) == DP_128b_132b_ENCODING &&
+	if (dp_get_link_encoding_format(link_settings) == DP_128b_132b_ENCODING &&
 			pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT &&
 			link->dc->debug.set_mst_en_for_sst) {
 		dp_enable_mst_on_sink(link, true);
@@ -2012,11 +2010,11 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 		link->dc->hwss.edp_wait_for_hpd_ready(link, true);
 	}
 
-	if (dp_get_link_encoding_format(&link_settings) == DP_128b_132b_ENCODING) {
+	if (dp_get_link_encoding_format(link_settings) == DP_128b_132b_ENCODING) {
 		/* TODO - DP2.0 HW: calculate 32 symbol clock for HPO encoder */
 	} else {
 		pipe_ctx->stream_res.pix_clk_params.requested_sym_clk =
-				link_settings.link_rate * LINK_RATE_REF_FREQ_IN_KHZ;
+				link_settings->link_rate * LINK_RATE_REF_FREQ_IN_KHZ;
 		if (state->clk_mgr && !apply_seamless_boot_optimization)
 			state->clk_mgr->funcs->update_clocks(state->clk_mgr,
 					state, false);
@@ -2032,16 +2030,15 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 
 	skip_video_pattern = true;
 
-	if (link_settings.link_rate == LINK_RATE_LOW)
+	if (link_settings->link_rate == LINK_RATE_LOW)
 		skip_video_pattern = false;
 
-	if (perform_link_training_with_retries(&link_settings,
+	if (perform_link_training_with_retries(link_settings,
 					       skip_video_pattern,
 					       LINK_TRAINING_ATTEMPTS,
 					       pipe_ctx,
 					       pipe_ctx->stream->signal,
 					       do_fallback)) {
-		link->cur_link_settings = link_settings;
 		status = DC_OK;
 	} else {
 		status = DC_FAIL_DP_LINK_TRAINING;
@@ -2052,7 +2049,7 @@ static enum dc_status enable_link_dp(struct dc_state *state,
 	else
 		fec_enable = true;
 
-	if (dp_get_link_encoding_format(&link_settings) == DP_8b_10b_ENCODING)
+	if (dp_get_link_encoding_format(link_settings) == DP_8b_10b_ENCODING)
 		dp_set_fec_enable(link, fec_enable);
 
 	// during mode set we do DP_SET_POWER off then on, aux writes are lost
@@ -4124,11 +4121,10 @@ static void fpga_dp_hpo_enable_link_and_stream(struct dc_state *state, struct pi
 	struct fixed31_32 avg_time_slots_per_mtp;
 	uint8_t req_slot_count = 0;
 	uint8_t vc_id = 1; /// VC ID always 1 for SST
-	struct dc_link_settings link_settings = {0};
+	struct dc_link_settings link_settings = pipe_ctx->link_config.dp_link_settings;
 	const struct link_hwss *link_hwss = get_link_hwss(stream->link, &pipe_ctx->link_res);
 	DC_LOGGER_INIT(pipe_ctx->stream->ctx->logger);
 
-	decide_link_settings(stream, &link_settings);
 	stream->link->cur_link_settings = link_settings;
 
 	if (link_hwss->ext.enable_dp_link_output)
@@ -4602,10 +4598,7 @@ void dc_link_set_preferred_link_settings(struct dc *dc,
 	if (link_stream->dpms_off)
 		return;
 
-	decide_link_settings(link_stream, &store_settings);
-
-	if ((store_settings.lane_count != LANE_COUNT_UNKNOWN) &&
-		(store_settings.link_rate != LINK_RATE_UNKNOWN))
+	if (decide_link_settings(link_stream, &store_settings))
 		dp_retrain_link_dp_test(link, &store_settings, false);
 }