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, 16 insertions, 29 deletions

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 a126921c664a..d380b8bc6f39 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
@@ -3880,15 +3880,13 @@ static bool decide_mst_link_settings(const struct dc_link *link, struct dc_link_
 	return true;
 }
 
-void decide_link_settings(struct dc_stream_state *stream,
+bool decide_link_settings(struct dc_stream_state *stream,
 	struct dc_link_settings *link_setting)
 {
-	struct dc_link *link;
-	uint32_t req_bw;
-
-	req_bw = dc_bandwidth_in_kbps_from_timing(&stream->timing);
+	struct dc_link *link = stream->link;
+	uint32_t req_bw = dc_bandwidth_in_kbps_from_timing(&stream->timing);
 
-	link = stream->link;
+	memset(link_setting, 0, sizeof(*link_setting));
 
 	/* if preferred is specified through AMDDP, use it, if it's enough
 	 * to drive the mode
@@ -3897,16 +3895,15 @@ void decide_link_settings(struct dc_stream_state *stream,
 			LANE_COUNT_UNKNOWN &&
 			link->preferred_link_setting.link_rate !=
 					LINK_RATE_UNKNOWN) {
-		*link_setting =  link->preferred_link_setting;
-		return;
+		*link_setting = link->preferred_link_setting;
+		return true;
 	}
 
 	/* MST doesn't perform link training for now
 	 * TODO: add MST specific link training routine
 	 */
 	if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
-		if (decide_mst_link_settings(link, link_setting))
-			return;
+		decide_mst_link_settings(link, link_setting);
 	} else if (link->connector_signal == SIGNAL_TYPE_EDP) {
 		/* enable edp link optimization for DSC eDP case */
 		if (stream->timing.flags.DSC) {
@@ -3924,17 +3921,16 @@ void decide_link_settings(struct dc_stream_state *stream,
 				decide_edp_link_settings(link, &tmp_link_setting, orig_req_bw);
 				max_link_rate = tmp_link_setting.link_rate;
 			}
-			if (decide_edp_link_settings_with_dsc(link, link_setting, req_bw, max_link_rate))
-				return;
-		} else if (decide_edp_link_settings(link, link_setting, req_bw))
-			return;
-	} else if (decide_dp_link_settings(link, link_setting, req_bw))
-		return;
-
-	BREAK_TO_DEBUGGER();
-	ASSERT(link->verified_link_cap.lane_count != LANE_COUNT_UNKNOWN);
+			decide_edp_link_settings_with_dsc(link, link_setting, req_bw, max_link_rate);
+		} else {
+			decide_edp_link_settings(link, link_setting, req_bw);
+		}
+	} else {
+		decide_dp_link_settings(link, link_setting, req_bw);
+	}
 
-	*link_setting = link->verified_link_cap;
+	return link_setting->lane_count != LANE_COUNT_UNKNOWN &&
+			link_setting->link_rate != LINK_RATE_UNKNOWN;
 }
 
 /*************************Short Pulse IRQ***************************/
@@ -4509,7 +4505,6 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 {
 	int i;
 	struct pipe_ctx *pipe_ctx;
-	struct dc_link_settings prev_link_settings = link->preferred_link_setting;
 
 	for (i = 0; i < MAX_PIPES; i++) {
 		pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
@@ -4520,10 +4515,6 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 	if (pipe_ctx == NULL || pipe_ctx->stream == NULL)
 		return;
 
-	/* toggle stream state with the preference for current link settings */
-	dc_link_set_preferred_training_settings((struct dc *)link->dc,
-					&link->cur_link_settings, NULL, link, true);
-
 	for (i = 0; i < MAX_PIPES; i++) {
 		pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
 		if (pipe_ctx && pipe_ctx->stream && !pipe_ctx->stream->dpms_off &&
@@ -4539,10 +4530,6 @@ void dc_link_dp_handle_link_loss(struct dc_link *link)
 			core_link_enable_stream(link->dc->current_state, pipe_ctx);
 		}
 	}
-
-	/* restore previous link settings preference */
-	dc_link_set_preferred_training_settings((struct dc *)link->dc,
-					&prev_link_settings, NULL, link, true);
 }
 
 bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd_irq_dpcd_data, bool *out_link_loss,