[PATCH v2 3/8] drm: zynqmp_dp: Adjust training values per-lane

[Sean Anderson]

The feedback we get from the DPRX is per-lane. Make changes using this
information, instead of picking the maximum values from all lanes. This
results in more-consistent training on marginal links.

Signed-off-by: Sean Anderson <sean.ander...@linux.dev>
---

(no changes since v1)

 drivers/gpu/drm/xlnx/zynqmp_dp.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 98a32e6a0459..8635b5673386 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -605,28 +605,21 @@ static void zynqmp_dp_adjust_train(struct zynqmp_dp *dp,
                                   u8 link_status[DP_LINK_STATUS_SIZE])
 {
        u8 *train_set = dp->train_set;
-       u8 voltage = 0, preemphasis = 0;
        u8 i;
 
        for (i = 0; i < dp->mode.lane_cnt; i++) {
-               u8 v = drm_dp_get_adjust_request_voltage(link_status, i);
-               u8 p = drm_dp_get_adjust_request_pre_emphasis(link_status, i);
+               u8 voltage = drm_dp_get_adjust_request_voltage(link_status, i);
+               u8 preemphasis =
+                       drm_dp_get_adjust_request_pre_emphasis(link_status, i);
 
-               if (v > voltage)
-                       voltage = v;
+               if (voltage >= DP_TRAIN_VOLTAGE_SWING_LEVEL_3)
+                       voltage |= DP_TRAIN_MAX_SWING_REACHED;
 
-               if (p > preemphasis)
-                       preemphasis = p;
-       }
+               if (preemphasis >= DP_TRAIN_PRE_EMPH_LEVEL_2)
+                       preemphasis |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
 
-       if (voltage >= DP_TRAIN_VOLTAGE_SWING_LEVEL_3)
-               voltage |= DP_TRAIN_MAX_SWING_REACHED;
-
-       if (preemphasis >= DP_TRAIN_PRE_EMPH_LEVEL_2)
-               preemphasis |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
-
-       for (i = 0; i < dp->mode.lane_cnt; i++)
                train_set[i] = voltage | preemphasis;
+       }
 }
 
 /**
-- 
2.35.1.1320.gc452695387.dirty