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

[Rodrigo Vivi]

From: "Vivi, Rodrigo" <rodrigo.vivi at intel.com>

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.
v3: Actually use n_entries and avoid duplicated -1.
v4: Avoid cnl_max_level and use current style.

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 | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index f1757a8e481a..1da3bb2cc4b4 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1879,10 +1879,17 @@ 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)) {
+		if (encoder->type == INTEL_OUTPUT_EDP)
+			cnl_get_buf_trans_edp(dev_priv, &n_entries);
+		else
+			cnl_get_buf_trans_dp(dev_priv, &n_entries);
+	} 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