drm/amd/display: Fix for null pointer access for ddc pin and aux engine.

[Why]
Need a check for NULL pointer access for ddc pin and aux engine.

[How]
Adding a check for ddc pin and aux engine accesses.
Reviewed-by: Jimmy Kizito <jimmy.kizito@amd.com>
Acked-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_hdcp.c

@@ -449,9 +449,7 @@ static void update_config(void *handle, struct cp_psp_stream_config *config)
 	struct mod_hdcp_link *link = &hdcp_work[link_index].link;
 	struct drm_connector_state *conn_state;
 	struct dc_sink *sink = NULL;
-#if defined(CONFIG_DRM_AMD_DC_DCN3_1)
 	bool link_is_hdcp14 = false;
-#endif
 
 	if (config->dpms_off) {
 		hdcp_remove_display(hdcp_work, link_index, aconnector);

drivers/gpu/drm/amd/display/dc/dce/dce_aux.c

@@ -689,8 +689,8 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 	enum aux_return_code_type operation_result;
 	bool retry_on_defer = false;
 	struct ddc *ddc_pin = ddc->ddc_pin;
-	struct dce_aux *aux_engine = ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en];
-	struct aux_engine_dce110 *aux110 = FROM_AUX_ENGINE(aux_engine);
+	struct dce_aux *aux_engine = NULL;
+	struct aux_engine_dce110 *aux110 = NULL;
 	uint32_t defer_time_in_ms = 0;
 
 	int aux_ack_retries = 0,
@@ -699,6 +699,11 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 		aux_timeout_retries = 0,
 		aux_invalid_reply_retries = 0;
 
+	if (ddc_pin) {
+		aux_engine = ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en];
+		aux110 = FROM_AUX_ENGINE(aux_engine);
+	}
+
 	if (!payload->reply) {
 		payload_reply = false;
 		payload->reply = &reply;
@@ -765,6 +770,7 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 							"dce_aux_transfer_with_retries: AUX_RET_SUCCESS: AUX_TRANSACTION_REPLY_AUX_DEFER");
 
 				/* polling_timeout_period is in us */
+				if (aux110)
 					defer_time_in_ms += aux110->polling_timeout_period / 1000;
 				++aux_defer_retries;
 				fallthrough;

drivers/gpu/drm/amd/display/include/dal_asic_id.h

@@ -227,7 +227,7 @@ enum {
 #define FAMILY_YELLOW_CARP                     146
 
 #define YELLOW_CARP_A0 0x01
-#define YELLOW_CARP_B0 0x02		// TODO: DCN31 - update with correct B0 ID
+#define YELLOW_CARP_B0 0x20
 #define YELLOW_CARP_UNKNOWN 0xFF
 
 #ifndef ASICREV_IS_YELLOW_CARP