[PATCH 06/38][SRU][G/H] drm/i915: Fix ivb cpu edp vswing

[You-Sheng Yang]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1903969

According to the DP spec supporting vswing 1 + preemph 2 is
mandatory. We don't have the hw settings for that though. In
order to pretend to follow the DP spec let's just select
vswing 0 + preemph 2 in this case (the DP spec says to use
the requested preemph in preference to the vswing when the
requested values aren't supported).

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-4-ville.syrjala@linux.intel.com
Reviewed-by: José Roberto de Souza <jose.souza at intel.com>
(cherry picked from commit 33520eae45f1c97670c8de7adec1cb5ab6a94416)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 00a63c6bc332..933a768f7094 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3997,8 +3997,6 @@ intel_dp_voltage_max(struct intel_dp *intel_dp)
 	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv) ||
 		 (HAS_PCH_SPLIT(dev_priv) && port != PORT_A))
 		return DP_TRAIN_VOLTAGE_SWING_LEVEL_3;
-	else if (IS_IVYBRIDGE(dev_priv) && port == PORT_A)
-		return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
 	else
 		return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
 }
@@ -4025,16 +4023,6 @@ intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, u8 voltage_swing)
 		default:
 			return DP_TRAIN_PRE_EMPH_LEVEL_0;
 		}
-	} else if (IS_IVYBRIDGE(dev_priv) && port == PORT_A) {
-		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
-		case DP_TRAIN_VOLTAGE_SWING_LEVEL_0:
-			return DP_TRAIN_PRE_EMPH_LEVEL_2;
-		case DP_TRAIN_VOLTAGE_SWING_LEVEL_1:
-		case DP_TRAIN_VOLTAGE_SWING_LEVEL_2:
-			return DP_TRAIN_PRE_EMPH_LEVEL_1;
-		default:
-			return DP_TRAIN_PRE_EMPH_LEVEL_0;
-		}
 	} else {
 		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
 		case DP_TRAIN_VOLTAGE_SWING_LEVEL_0:
@@ -4330,6 +4318,7 @@ static u32 ivb_cpu_edp_signal_levels(u8 train_set)
 	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_1:
 		return EDP_LINK_TRAIN_400MV_3_5DB_IVB;
 	case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_2:
+	case DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_2:
 		return EDP_LINK_TRAIN_400MV_6DB_IVB;
 
 	case DP_TRAIN_VOLTAGE_SWING_LEVEL_1 | DP_TRAIN_PRE_EMPH_LEVEL_0:
-- 
2.29.2