[Intel-gfx] [PATCH 6/6] drm/i915/cnl: Fix DP max voltage

[Rodrigo Vivi]

On clock recovery this function is called to find out
the max voltage swing level that we could go.

However gen 9 functions use the old buffer translation tables
to figure that out. That table is not valid for CNL
causing an invalid number of entries and an invalid selection
on the max voltage swing level.

v2: Let's use same approach that previous platforms.

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Clint Taylor <clinton.a.taylor at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 51d59e3e1776..a71d6816c522 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -649,6 +649,29 @@ cnl_get_buf_trans_edp(struct drm_i915_private *dev_priv, int *n_entries)
 	}
 }
 
+static int cnl_max_level(struct drm_i915_private *dev_priv,
+			 enum intel_output_type type)
+{
+	int n_entries = 0;
+
+	switch (type) {
+	case INTEL_OUTPUT_DP:
+		cnl_get_buf_trans_dp(dev_priv, &n_entries);
+		break;
+	case INTEL_OUTPUT_EDP:
+		cnl_get_buf_trans_edp(dev_priv, &n_entries);
+		break;
+	case INTEL_OUTPUT_HDMI:
+		cnl_get_buf_trans_hdmi(dev_priv, &n_entries);
+		break;
+	default:
+		MISSING_CASE(type);
+		return 0;
+	}
+
+	return n_entries - 1;
+}
+
 static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port port)
 {
 	int n_hdmi_entries;
@@ -1879,10 +1902,14 @@ u8 intel_ddi_dp_voltage_max(struct intel_encoder *encoder)
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	int n_entries;
 
-	if (encoder->type == INTEL_OUTPUT_EDP)
-		intel_ddi_get_buf_trans_edp(dev_priv, &n_entries);
-	else
-		intel_ddi_get_buf_trans_dp(dev_priv, &n_entries);
+	if (IS_CANNONLAKE(dev_priv)) {
+		cnl_max_level(dev_priv, encoder->type);
+	} else {
+		if (encoder->type == INTEL_OUTPUT_EDP)
+			intel_ddi_get_buf_trans_edp(dev_priv, &n_entries);
+		else
+			intel_ddi_get_buf_trans_dp(dev_priv, &n_entries);
+	}
 
 	if (WARN_ON(n_entries < 1))
 		n_entries = 1;
-- 
2.13.2