drm/i915: Program iboost settings for HDMI/DVI on SKL

Currently we fail to program the iboost stuff for HDMI/DVI. Let's remedy
that.

Cc: stable@vger.kernel.org
Fixes: f8896f5d58e6 ("drm/i915/skl: Buffer translation improvements")
Cc: David Weinehall <david.weinehall@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1468328376-6380-4-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
(cherry picked from commit 8d8bb85eb7d859aa9bbe36e588690a1d22af7608)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_ddi.c

@@ -388,6 +388,40 @@ skl_get_buf_trans_hdmi(struct drm_i915_private *dev_priv, int *n_entries)
 	}
 }
 
+static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port port)
+{
+	int n_hdmi_entries;
+	int hdmi_level;
+	int hdmi_default_entry;
+
+	hdmi_level = dev_priv->vbt.ddi_port_info[port].hdmi_level_shift;
+
+	if (IS_BROXTON(dev_priv))
+		return hdmi_level;
+
+	if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv)) {
+		skl_get_buf_trans_hdmi(dev_priv, &n_hdmi_entries);
+		hdmi_default_entry = 8;
+	} else if (IS_BROADWELL(dev_priv)) {
+		n_hdmi_entries = ARRAY_SIZE(bdw_ddi_translations_hdmi);
+		hdmi_default_entry = 7;
+	} else if (IS_HASWELL(dev_priv)) {
+		n_hdmi_entries = ARRAY_SIZE(hsw_ddi_translations_hdmi);
+		hdmi_default_entry = 6;
+	} else {
+		WARN(1, "ddi translation table missing\n");
+		n_hdmi_entries = ARRAY_SIZE(bdw_ddi_translations_hdmi);
+		hdmi_default_entry = 7;
+	}
+
+	/* Choose a good default if VBT is badly populated */
+	if (hdmi_level == HDMI_LEVEL_SHIFT_UNKNOWN ||
+	    hdmi_level >= n_hdmi_entries)
+		hdmi_level = hdmi_default_entry;
+
+	return hdmi_level;
+}
+
 /*
  * Starting with Haswell, DDI port buffers must be programmed with correct
  * values in advance. The buffer values are different for FDI and DP modes,
@@ -399,7 +433,7 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	u32 iboost_bit = 0;
-	int i, n_hdmi_entries, n_dp_entries, n_edp_entries, hdmi_default_entry,
+	int i, n_hdmi_entries, n_dp_entries, n_edp_entries,
 	    size;
 	int hdmi_level;
 	enum port port;
@@ -410,7 +444,7 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 	const struct ddi_buf_trans *ddi_translations;
 
 	port = intel_ddi_get_encoder_port(encoder);
-	hdmi_level = dev_priv->vbt.ddi_port_info[port].hdmi_level_shift;
+	hdmi_level = intel_ddi_hdmi_level(dev_priv, port);
 
 	if (IS_BROXTON(dev_priv)) {
 		if (encoder->type != INTEL_OUTPUT_HDMI)
@@ -430,7 +464,6 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 				skl_get_buf_trans_edp(dev_priv, &n_edp_entries);
 		ddi_translations_hdmi =
 				skl_get_buf_trans_hdmi(dev_priv, &n_hdmi_entries);
-		hdmi_default_entry = 8;
 		/* If we're boosting the current, set bit 31 of trans1 */
 		if (dev_priv->vbt.ddi_port_info[port].hdmi_boost_level ||
 		    dev_priv->vbt.ddi_port_info[port].dp_boost_level)
@@ -456,7 +489,6 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 
 		n_dp_entries = ARRAY_SIZE(bdw_ddi_translations_dp);
 		n_hdmi_entries = ARRAY_SIZE(bdw_ddi_translations_hdmi);
-		hdmi_default_entry = 7;
 	} else if (IS_HASWELL(dev_priv)) {
 		ddi_translations_fdi = hsw_ddi_translations_fdi;
 		ddi_translations_dp = hsw_ddi_translations_dp;
@@ -464,7 +496,6 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 		ddi_translations_hdmi = hsw_ddi_translations_hdmi;
 		n_dp_entries = n_edp_entries = ARRAY_SIZE(hsw_ddi_translations_dp);
 		n_hdmi_entries = ARRAY_SIZE(hsw_ddi_translations_hdmi);
-		hdmi_default_entry = 6;
 	} else {
 		WARN(1, "ddi translation table missing\n");
 		ddi_translations_edp = bdw_ddi_translations_dp;
@@ -474,7 +505,6 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 		n_edp_entries = ARRAY_SIZE(bdw_ddi_translations_edp);
 		n_dp_entries = ARRAY_SIZE(bdw_ddi_translations_dp);
 		n_hdmi_entries = ARRAY_SIZE(bdw_ddi_translations_hdmi);
-		hdmi_default_entry = 7;
 	}
 
 	switch (encoder->type) {
@@ -505,11 +535,6 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
 	if (encoder->type != INTEL_OUTPUT_HDMI)
 		return;
 
-	/* Choose a good default if VBT is badly populated */
-	if (hdmi_level == HDMI_LEVEL_SHIFT_UNKNOWN ||
-	    hdmi_level >= n_hdmi_entries)
-		hdmi_level = hdmi_default_entry;
-
 	/* Entry 9 is for HDMI: */
 	I915_WRITE(DDI_BUF_TRANS_LO(port, i),
 		   ddi_translations_hdmi[hdmi_level].trans1 | iboost_bit);
@@ -1647,6 +1672,10 @@ static void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
 			intel_dp_stop_link_train(intel_dp);
 	} else if (type == INTEL_OUTPUT_HDMI) {
 		struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
+		int level = intel_ddi_hdmi_level(dev_priv, port);
+
+		if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv))
+			skl_ddi_set_iboost(intel_encoder, level);
 
 		intel_hdmi->set_infoframes(encoder,
 					   crtc->config->has_hdmi_sink,