drm/amd/display: Fix dynamic encoder reassignment

[Why]
Incorrect encoder assignments were being used while applying a new state
to hardware.

(1) When committing a new state to hardware requires resetting the
back-end, the encoder assignments of the current or old state should be
used when disabling the back-end; and the encoder assignments for the
next or new state should be used when re-enabling the back-end.

(2) Link training on hot plug could take over an encoder already in use
by another stream without first disabling it.

[How]

(1) Introduce a resource context 'link_enc_cfg_context' which includes:
- a mode to indicate when transitioning from current to next state.
- transient encoder assignments to use during this state transition.

Update the encoder configuration interface to respond to queries about
encoder assignment based on the mode of operation.

(2) Check if an encoder is already in use before attempting to perform
link training on hot plug.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 16 insertions, 11 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 2a58de375d8f..0fe0eb06eacc 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
@@ -304,7 +304,7 @@ static enum dc_dp_training_pattern decide_eq_training_pattern(struct dc_link *li
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign)
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 	else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);
@@ -339,7 +339,7 @@ static enum dc_dp_training_pattern decide_eq_training_pattern(struct dc_link *li
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign)
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 	else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);
@@ -2385,7 +2385,7 @@ bool perform_link_training_with_retries(
 	 * link.
 	 */
 	if (link->is_dig_mapping_flexible && link->dc->res_pool->funcs->link_encs_assign)
-		link_enc = stream->link_enc;
+		link_enc = link_enc_cfg_get_link_enc_used_by_stream(link->ctx->dc, pipe_ctx->stream);
 	else
 		link_enc = link->link_enc;
 
@@ -2666,9 +2666,9 @@ bool dc_link_dp_get_max_link_enc_cap(const struct dc_link *link, struct dc_link_
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign) {
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 		if (link_enc == NULL)
-			link_enc = link_enc_cfg_get_next_avail_link_enc(link->dc, link->dc->current_state);
+			link_enc = link_enc_cfg_get_next_avail_link_enc(link->ctx->dc);
 	} else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);
@@ -2697,9 +2697,9 @@ static struct dc_link_settings get_max_link_cap(struct dc_link *link)
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign) {
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 		if (link_enc == NULL)
-			link_enc = link_enc_cfg_get_next_avail_link_enc(link->dc, link->dc->current_state);
+			link_enc = link_enc_cfg_get_next_avail_link_enc(link->ctx->dc);
 	} else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);
@@ -2881,7 +2881,13 @@ bool dp_verify_link_cap(
 	enum link_training_result status;
 	union hpd_irq_data irq_data;
 
-	if (link->dc->debug.skip_detection_link_training) {
+	/* Accept reported capabilities if link supports flexible encoder mapping or encoder already in use. */
+	if (link->dc->debug.skip_detection_link_training ||
+			link->is_dig_mapping_flexible) {
+		link->verified_link_cap = *known_limit_link_setting;
+		return true;
+	} else if (link->link_enc && link->dc->res_pool->funcs->link_encs_assign &&
+			!link_enc_cfg_is_link_enc_avail(link->ctx->dc, link->link_enc->preferred_engine)) {
 		link->verified_link_cap = *known_limit_link_setting;
 		return true;
 	}
@@ -5679,7 +5685,7 @@ enum dc_status dp_set_fec_ready(struct dc_link *link, bool ready)
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign)
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 	else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);
@@ -5726,8 +5732,7 @@ void dp_set_fec_enable(struct dc_link *link, bool enable)
 	 */
 	if (link->is_dig_mapping_flexible &&
 			link->dc->res_pool->funcs->link_encs_assign)
-		link_enc = link_enc_cfg_get_link_enc_used_by_link(
-				link->dc->current_state, link);
+		link_enc = link_enc_cfg_get_link_enc_used_by_link(link->ctx->dc, link);
 	else
 		link_enc = link->link_enc;
 	ASSERT(link_enc);