From: Kuogee Hsieh <[email protected]>

Some DP sinkers prefer to use tps4 instead of tps3 during training #2.
This patch will use tps4 to perform link training #2 if sinker's DPCD
supports it.

Signed-off-by: Kuogee Hsieh <[email protected]>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 39558a2..c7b0657 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1181,7 +1181,7 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private 
*ctrl,
                        int *training_step)
 {
        int tries = 0, ret = 0;
-       char pattern;
+       char pattern, state_ctrl_bit;
        int const maximum_retries = 5;
        u8 link_status[DP_LINK_STATUS_SIZE];
 
@@ -1189,12 +1189,20 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private 
*ctrl,
 
        *training_step = DP_TRAINING_2;
 
-       if (drm_dp_tps3_supported(ctrl->panel->dpcd))
+       if (drm_dp_tps4_supported(ctrl->panel->dpcd)) {
+               pattern = DP_TRAINING_PATTERN_4;
+               state_ctrl_bit = 4;
+       }
+       else if (drm_dp_tps3_supported(ctrl->panel->dpcd)) {
                pattern = DP_TRAINING_PATTERN_3;
-       else
+               state_ctrl_bit = 3;
+       }
+       else {
                pattern = DP_TRAINING_PATTERN_2;
+               state_ctrl_bit = 2;
+       }
 
-       ret = dp_catalog_ctrl_set_pattern(ctrl->catalog, pattern);
+       ret = dp_catalog_ctrl_set_pattern(ctrl->catalog, state_ctrl_bit);
        if (ret)
                return ret;
 
-- 
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