[Intel-gfx] [PATCH v2 3/5] drm/i915: Remove DDC pin sanitation

[Ville Syrjala <ville.syrjala@linux.intel.com>]

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

Stop with the VBT DDC pin sanitation, and instead just check
that the appropriate DDC pin is still available when initializing
a HDMI connector.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c | 69 ----------------------
 drivers/gpu/drm/i915/display/intel_hdmi.c | 72 +++++++++++++++++++----
 2 files changed, 59 insertions(+), 82 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 34a397adbd6b..439ab5b3cbe5 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -2230,72 +2230,6 @@ static u8 map_ddc_pin(struct drm_i915_private *i915, u8 vbt_pin)
 	return 0;
 }
 
-static enum port get_port_by_ddc_pin(struct drm_i915_private *i915, u8 ddc_pin)
-{
-	enum port port;
-
-	if (!ddc_pin)
-		return PORT_NONE;
-
-	for_each_port(port) {
-		const struct intel_bios_encoder_data *devdata =
-			i915->display.vbt.ports[port];
-
-		if (devdata && ddc_pin == devdata->child.ddc_pin)
-			return port;
-	}
-
-	return PORT_NONE;
-}
-
-static void sanitize_ddc_pin(struct intel_bios_encoder_data *devdata,
-			     enum port port)
-{
-	struct drm_i915_private *i915 = devdata->i915;
-	struct child_device_config *child;
-	u8 mapped_ddc_pin;
-	enum port p;
-
-	if (!devdata->child.ddc_pin)
-		return;
-
-	mapped_ddc_pin = map_ddc_pin(i915, devdata->child.ddc_pin);
-	if (!intel_gmbus_is_valid_pin(i915, mapped_ddc_pin)) {
-		drm_dbg_kms(&i915->drm,
-			    "Port %c has invalid DDC pin %d, "
-			    "sticking to defaults\n",
-			    port_name(port), mapped_ddc_pin);
-		devdata->child.ddc_pin = 0;
-		return;
-	}
-
-	p = get_port_by_ddc_pin(i915, devdata->child.ddc_pin);
-	if (p == PORT_NONE)
-		return;
-
-	drm_dbg_kms(&i915->drm,
-		    "port %c trying to use the same DDC pin (0x%x) as port %c, "
-		    "disabling port %c DVI/HDMI support\n",
-		    port_name(port), mapped_ddc_pin,
-		    port_name(p), port_name(p));
-
-	/*
-	 * If we have multiple ports supposedly sharing the pin, then dvi/hdmi
-	 * couldn't exist on the shared port. Otherwise they share the same ddc
-	 * pin and system couldn't communicate with them separately.
-	 *
-	 * Give inverse child device order the priority, last one wins. Yes,
-	 * there are real machines (eg. Asrock B250M-HDV) where VBT has both
-	 * port A and port E with the same AUX ch and we must pick port E :(
-	 */
-	child = &i915->display.vbt.ports[p]->child;
-
-	child->device_type &= ~DEVICE_TYPE_TMDS_DVI_SIGNALING;
-	child->device_type |= DEVICE_TYPE_NOT_HDMI_OUTPUT;
-
-	child->ddc_pin = 0;
-}
-
 static enum port get_port_by_aux_ch(struct drm_i915_private *i915, u8 aux_ch)
 {
 	enum port port;
@@ -2753,9 +2687,6 @@ static void parse_ddi_port(struct intel_bios_encoder_data *devdata)
 
 	sanitize_device_type(devdata, port);
 
-	if (intel_bios_encoder_supports_dvi(devdata))
-		sanitize_ddc_pin(devdata, port);
-
 	if (intel_bios_encoder_supports_dp(devdata))
 		sanitize_aux_ch(devdata, port);
 
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 7ac5e6c5e00d..8d1c8abfcffa 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2880,21 +2880,12 @@ static u8 g4x_port_to_ddc_pin(struct drm_i915_private *dev_priv,
 	return ddc_pin;
 }
 
-static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
+static u8 intel_hdmi_default_ddc_pin(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	enum port port = encoder->port;
 	u8 ddc_pin;
 
-	ddc_pin = intel_bios_hdmi_ddc_pin(encoder->devdata);
-	if (ddc_pin) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "[ENCODER:%d:%s] Using DDC pin 0x%x (VBT)\n",
-			    encoder->base.base.id, encoder->base.name,
-			    ddc_pin);
-		return ddc_pin;
-	}
-
 	if (IS_ALDERLAKE_S(dev_priv))
 		ddc_pin = adls_port_to_ddc_pin(dev_priv, port);
 	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
@@ -2916,10 +2907,62 @@ static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
 	else
 		ddc_pin = g4x_port_to_ddc_pin(dev_priv, port);
 
-	drm_dbg_kms(&dev_priv->drm,
-		    "[ENCODER:%d:%s] Using DDC pin 0x%x (platform default)\n",
+	return ddc_pin;
+}
+
+static struct intel_encoder *
+get_encoder_by_ddc_pin(struct intel_encoder *encoder, u8 ddc_pin)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct intel_encoder *other;
+
+	for_each_intel_encoder(&i915->drm, other) {
+		if (other == encoder)
+			continue;
+
+		if (!intel_encoder_is_dig_port(other))
+			continue;
+
+		if (enc_to_dig_port(other)->hdmi.ddc_bus == ddc_pin)
+			return other;
+	}
+
+	return NULL;
+}
+
+static u8 intel_hdmi_ddc_pin(struct intel_encoder *encoder)
+{
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct intel_encoder *other;
+	const char *source;
+	u8 ddc_pin;
+
+	ddc_pin = intel_bios_hdmi_ddc_pin(encoder->devdata);
+	source = "VBT";
+
+	if (!ddc_pin) {
+		ddc_pin = intel_hdmi_default_ddc_pin(encoder);
+		source = "platform default";
+	}
+
+	if (!intel_gmbus_is_valid_pin(i915, ddc_pin)) {
+		drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] Invalid DDC pin %d\n",
+			    encoder->base.base.id, encoder->base.name, ddc_pin);
+		return 0;
+	}
+
+	other = get_encoder_by_ddc_pin(encoder, ddc_pin);
+	if (other) {
+		drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] DDC pin %d already claimed by [ENCODER:%d:%s]\n",
+			    encoder->base.base.id, encoder->base.name, ddc_pin,
+			    other->base.base.id, other->base.name);
+		return 0;
+	}
+
+	drm_dbg_kms(&i915->drm,
+		    "[ENCODER:%d:%s] Using DDC pin 0x%x (%s)\n",
 		    encoder->base.base.id, encoder->base.name,
-		    ddc_pin);
+		    ddc_pin, source);
 
 	return ddc_pin;
 }
@@ -2990,6 +3033,9 @@ void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
 		return;
 
 	intel_hdmi->ddc_bus = intel_hdmi_ddc_pin(intel_encoder);
+	if (!intel_hdmi->ddc_bus)
+		return;
+
 	ddc = intel_gmbus_get_adapter(dev_priv, intel_hdmi->ddc_bus);
 
 	drm_connector_init_with_ddc(dev, connector,
-- 
2.39.3