[Intel-gfx] [PATCH v3 22/22] drm/i915: Only populate aux_ch is really needed

[Ville Syrjala]

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

Mixing VBT based AUX CH with platform defaults seems like
a recipe for conflicts. Let's only populate AUX CH if we
absolutely need it, that is only if we are dealing with
a DP output or a TC port (which need ot due to some power
well shenanigans).

TODO: double check that real VBTs do in fact populate
      the AUX CH for HDMI TC legacy ports...

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/g4x_hdmi.c  |  1 -
 drivers/gpu/drm/i915/display/intel_ddi.c | 16 +++++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/g4x_hdmi.c b/drivers/gpu/drm/i915/display/g4x_hdmi.c
index 7c66deb457ae..eb5bdad98590 100644
--- a/drivers/gpu/drm/i915/display/g4x_hdmi.c
+++ b/drivers/gpu/drm/i915/display/g4x_hdmi.c
@@ -662,7 +662,6 @@ void g4x_hdmi_init(struct drm_i915_private *dev_priv,
 	dig_port->max_lanes = 4;
 
 	intel_infoframe_init(dig_port);
 
-	dig_port->aux_ch = intel_dp_aux_ch(intel_encoder);
 	intel_hdmi_init_connector(dig_port, intel_connector);
 }
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 1208bfcd4e30..4a23e1e58261 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4298,8 +4298,16 @@ static bool port_strap_detected(struct drm_i915_private *i915, enum port port)
 		return false;
 	}
 }
 
+static bool need_aux_ch(struct intel_encoder *encoder, bool init_dp)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	enum phy phy = intel_port_to_phy(i915, encoder->port);
+
+	return init_dp || intel_phy_is_tc(i915, phy);
+}
+
 void intel_ddi_init(struct drm_i915_private *dev_priv,
 		    struct intel_bios_encoder_data *devdata,
 		    enum port port)
 {
@@ -4558,11 +4566,13 @@ void intel_ddi_init(struct drm_i915_private *dev_priv,
 
 	dig_port->dp.output_reg = INVALID_MMIO_REG;
 	dig_port->max_lanes = intel_ddi_max_lanes(dig_port);
 
-	dig_port->aux_ch = intel_dp_aux_ch(encoder);
-	if (dig_port->aux_ch == AUX_CH_NONE)
-		goto err;
+	if (need_aux_ch(encoder, init_dp)) {
+		dig_port->aux_ch = intel_dp_aux_ch(encoder);
+		if (dig_port->aux_ch == AUX_CH_NONE)
+			goto err;
+	}
 
 	if (intel_phy_is_tc(dev_priv, phy)) {
 		bool is_legacy =
 			!intel_bios_encoder_supports_typec_usb(devdata) &&
-- 
2.39.2