drm/amd/display: Don't return ddc result and read_bytes in same return value

The two ranges overlap.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

3 files changed, 22 insertions, 13 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index ace9ad578ca0..4304d9e408b8 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -83,21 +83,22 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
         enum i2c_mot_mode mot = (msg->request & DP_AUX_I2C_MOT) ?
                 I2C_MOT_TRUE : I2C_MOT_FALSE;
         enum ddc_result res;
-        ssize_t read_bytes;
+        uint32_t read_bytes = msg->size;
 
         if (WARN_ON(msg->size > 16))
                 return -E2BIG;
 
         switch (msg->request & ~DP_AUX_I2C_MOT) {
         case DP_AUX_NATIVE_READ:
-                read_bytes = dal_ddc_service_read_dpcd_data(
+                res = dal_ddc_service_read_dpcd_data(
                                 TO_DM_AUX(aux)->ddc_service,
                                 false,
                                 I2C_MOT_UNDEF,
                                 msg->address,
                                 msg->buffer,
-                                msg->size);
-                return read_bytes;
+                                msg->size,
+                                &read_bytes);
+                break;
         case DP_AUX_NATIVE_WRITE:
                 res = dal_ddc_service_write_dpcd_data(
                                 TO_DM_AUX(aux)->ddc_service,
@@ -108,14 +109,15 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
                                 msg->size);
                 break;
         case DP_AUX_I2C_READ:
-                read_bytes = dal_ddc_service_read_dpcd_data(
+                res = dal_ddc_service_read_dpcd_data(
                                 TO_DM_AUX(aux)->ddc_service,
                                 true,
                                 mot,
                                 msg->address,
                                 msg->buffer,
-                                msg->size);
-                return read_bytes;
+                                msg->size,
+                                &read_bytes);
+                break;
         case DP_AUX_I2C_WRITE:
                 res = dal_ddc_service_write_dpcd_data(
                                 TO_DM_AUX(aux)->ddc_service,
@@ -137,7 +139,9 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
                  r == DDC_RESULT_SUCESSFULL);
 #endif
 
-        return msg->size;
+        if (res != DDC_RESULT_SUCESSFULL)
+                return -EIO;
+        return read_bytes;
 }
 
 static enum drm_connector_status
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
index 49c2face1e7a..ae48d603ebd6 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c
@@ -629,13 +629,14 @@ bool dal_ddc_service_query_ddc_data(
         return ret;
 }
 
-ssize_t dal_ddc_service_read_dpcd_data(
+enum ddc_result dal_ddc_service_read_dpcd_data(
         struct ddc_service *ddc,
         bool i2c,
         enum i2c_mot_mode mot,
         uint32_t address,
         uint8_t *data,
-        uint32_t len)
+        uint32_t len,
+        uint32_t *read)
 {
         struct aux_payload read_payload = {
                 .i2c_over_aux = i2c,
@@ -652,6 +653,8 @@ ssize_t dal_ddc_service_read_dpcd_data(
                 .mot = mot
         };
 
+        *read = 0;
+
         if (len > DEFAULT_AUX_MAX_DATA_SIZE) {
                 BREAK_TO_DEBUGGER();
                 return DDC_RESULT_FAILED_INVALID_OPERATION;
@@ -661,7 +664,8 @@ ssize_t dal_ddc_service_read_dpcd_data(
                 ddc->ctx->i2caux,
                 ddc->ddc_pin,
                 &command)) {
-                return (ssize_t)command.payloads->length;
+                *read = command.payloads->length;
+                return DDC_RESULT_SUCESSFULL;
         }
 
         return DDC_RESULT_FAILED_OPERATION;
diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_ddc.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_ddc.h
index 090b7a8dd67b..30b3a08b91be 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_ddc.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_ddc.h
@@ -102,13 +102,14 @@ bool dal_ddc_service_query_ddc_data(
                 uint8_t *read_buf,
                 uint32_t read_size);
 
-ssize_t dal_ddc_service_read_dpcd_data(
+enum ddc_result dal_ddc_service_read_dpcd_data(
                 struct ddc_service *ddc,
                 bool i2c,
                 enum i2c_mot_mode mot,
                 uint32_t address,
                 uint8_t *data,
-                uint32_t len);
+                uint32_t len,
+                uint32_t *read);
 
 enum ddc_result dal_ddc_service_write_dpcd_data(
                 struct ddc_service *ddc,