drm/amd/display: Add aconnector condition check for dpcd read

[Why]
core_link_read_dpcd() will invoke dm_helpers_dp_read_dpcd(),
which needs to read dpcd info with the help of aconnector.
If aconnector (dc->links[i]->prev) is NULL, then dpcd status
 cannot be read.

As a result, dpcd read fails and a line of error will be
printed out in dmesg.log as:
"*ERROR* Failed to found connector for link!"

[How]
Make sure that aconnector (dc->links[i]->prev) is not NULL,
then read dpcd status.

Signed-off-by: Zhan Liu <zhan.liu@amd.com>
Reviewed-by: Joseph Gravenor <Joseph.Gravenor@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 5f56cc1..af40ea5 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -1328,14 +1328,21 @@ void dcn10_init_hw(struct dc *dc)
                enum dc_status status = DC_ERROR_UNEXPECTED;
 
                for (i = 0; i < dc->link_count; i++) {
-                       if (dc->links[i]->connector_signal != SIGNAL_TYPE_DISPLAY_PORT) {
+                       if (dc->links[i]->connector_signal != SIGNAL_TYPE_DISPLAY_PORT)
                                continue;
-                       }
-                       /* if any of the displays are lit up turn them off */
-                       status = core_link_read_dpcd(dc->links[i], DP_SET_POWER,
-                                                    &dpcd_power_state, sizeof(dpcd_power_state));
-                       if (status == DC_OK && dpcd_power_state == DP_POWER_STATE_D0) {
-                               dp_receiver_power_ctrl(dc->links[i], false);
+
+                       /*
+                        * core_link_read_dpcd() will invoke dm_helpers_dp_read_dpcd(),
+                        * which needs to read dpcd info with the help of aconnector.
+                        * If aconnector (dc->links[i]->prev) is NULL, then dpcd status
+                        * cannot be read.
+                        */
+                       if (dc->links[i]->priv) {
+                               /* if any of the displays are lit up turn them off */
+                               status = core_link_read_dpcd(dc->links[i], DP_SET_POWER,
+                                                               &dpcd_power_state, sizeof(dpcd_power_state));
+                               if (status == DC_OK && dpcd_power_state == DP_POWER_STATE_D0)
+                                       dp_receiver_power_ctrl(dc->links[i], false);
                        }
                }
        }