drm/bridge: analogix_dp: don't adjust further when clock recovery succeeded

Take a early return from the clock recovery training when the sink reports
CR_DONE for all lanes. There is no point in trying to adjust the link
parameters further.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240318203925.2837689-3-l.stach@pengutronix.de

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 89d7c30e393ff31e7c584c50f52c6e01ecb6bb8c..b5dbff21c18734ba9c3d8326fd039e5c4b48e9f6 100644 (file)
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -410,11 +410,6 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
        if (retval < 0)
                return retval;
 
-       retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
-                                 adjust_request, 2);
-       if (retval < 0)
-               return retval;
-
        if (analogix_dp_clock_recovery_ok(link_status, lane_count) == 0) {
                /* set training pattern 2 for EQ */
                analogix_dp_set_training_pattern(dp, TRAINING_PTN2);
@@ -427,30 +422,32 @@ static int analogix_dp_process_clock_recovery(struct analogix_dp_device *dp)
 
                dev_dbg(dp->dev, "Link Training Clock Recovery success\n");
                dp->link_train.lt_state = EQUALIZER_TRAINING;
-       } else {
-               for (lane = 0; lane < lane_count; lane++) {
-                       training_lane = analogix_dp_get_lane_link_training(
-                                                       dp, lane);
-                       voltage_swing = analogix_dp_get_adjust_request_voltage(
-                                                       adjust_request, lane);
-                       pre_emphasis = analogix_dp_get_adjust_request_pre_emphasis(
-                                                       adjust_request, lane);
-
-                       if (DPCD_VOLTAGE_SWING_GET(training_lane) ==
-                                       voltage_swing &&
-                           DPCD_PRE_EMPHASIS_GET(training_lane) ==
-                                       pre_emphasis)
-                               dp->link_train.cr_loop[lane]++;
-
-                       if (dp->link_train.cr_loop[lane] == MAX_CR_LOOP ||
-                           voltage_swing == VOLTAGE_LEVEL_3 ||
-                           pre_emphasis == PRE_EMPHASIS_LEVEL_3) {
-                               dev_err(dp->dev, "CR Max reached (%d,%d,%d)\n",
-                                       dp->link_train.cr_loop[lane],
-                                       voltage_swing, pre_emphasis);
-                               analogix_dp_reduce_link_rate(dp);
-                               return -EIO;
-                       }
+
+               return 0;
+       }
+
+       retval = drm_dp_dpcd_read(&dp->aux, DP_ADJUST_REQUEST_LANE0_1,
+                                 adjust_request, 2);
+       if (retval < 0)
+               return retval;
+
+       for (lane = 0; lane < lane_count; lane++) {
+               training_lane = analogix_dp_get_lane_link_training(dp, lane);
+               voltage_swing = analogix_dp_get_adjust_request_voltage(adjust_request, lane);
+               pre_emphasis = analogix_dp_get_adjust_request_pre_emphasis(adjust_request, lane);
+
+               if (DPCD_VOLTAGE_SWING_GET(training_lane) == voltage_swing &&
+                   DPCD_PRE_EMPHASIS_GET(training_lane) == pre_emphasis)
+                       dp->link_train.cr_loop[lane]++;
+
+               if (dp->link_train.cr_loop[lane] == MAX_CR_LOOP ||
+                   voltage_swing == VOLTAGE_LEVEL_3 ||
+                   pre_emphasis == PRE_EMPHASIS_LEVEL_3) {
+                       dev_err(dp->dev, "CR Max reached (%d,%d,%d)\n",
+                               dp->link_train.cr_loop[lane],
+                               voltage_swing, pre_emphasis);
+                       analogix_dp_reduce_link_rate(dp);
+                       return -EIO;
                }
        }