[PATCH 13/19] drm/amd/display: Fix for null pointer access for ddc pin and aux engine.

[Mikita Lipski]

From: Meenakshikumar Somasundaram <meenakshikumar.somasundaram at amd.com>

[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 at amd.com>
Acked-by: Mikita Lipski <mikita.lipski at amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_aux.c      | 12 +++++++++---
 drivers/gpu/drm/amd/display/include/dal_asic_id.h |  2 +-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
index 2fb88e54a4bf..a75487ed1bb6 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c
@@ -630,8 +630,8 @@ 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,
@@ -640,6 +640,11 @@ 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;
@@ -666,7 +671,8 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 
 			case AUX_TRANSACTION_REPLY_AUX_DEFER:
 				/* polling_timeout_period is in us */
-				defer_time_in_ms += aux110->polling_timeout_period / 1000;
+				if (aux110)
+					defer_time_in_ms += aux110->polling_timeout_period / 1000;
 				++aux_defer_retries;
 				fallthrough;
 			case AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER:
diff --git a/drivers/gpu/drm/amd/display/include/dal_asic_id.h b/drivers/gpu/drm/amd/display/include/dal_asic_id.h
index 381c17caace1..3d2f0817e40a 100644
--- a/drivers/gpu/drm/amd/display/include/dal_asic_id.h
+++ b/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
-- 
2.25.1