4 files changed, 50 insertions, 62 deletions

diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
index 0cab5992e3da..4c7187f7913e 100644
--- a/drivers/gpu/drm/i915/display/g4x_dp.c
+++ b/drivers/gpu/drm/i915/display/g4x_dp.c
@@ -1378,6 +1378,9 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
 		intel_infoframe_init(dig_port);
 
 	dig_port->aux_ch = intel_dp_aux_ch(intel_encoder);
+	if (dig_port->aux_ch == AUX_CH_NONE)
+		goto err_init_connector;
+
 	if (!intel_dp_init_connector(dig_port, intel_connector))
 		goto err_init_connector;
 
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 6aeebd3c97f9..ae83788177ce 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -2230,56 +2230,6 @@ static u8 map_ddc_pin(struct drm_i915_private *i915, u8 vbt_pin)
 	return 0;
 }
 
-static enum port get_port_by_aux_ch(struct drm_i915_private *i915, u8 aux_ch)
-{
-	enum port port;
-
-	if (!aux_ch)
-		return PORT_NONE;
-
-	for_each_port(port) {
-		const struct intel_bios_encoder_data *devdata =
-			i915->display.vbt.ports[port];
-
-		if (devdata && aux_ch == devdata->child.aux_channel)
-			return port;
-	}
-
-	return PORT_NONE;
-}
-
-static void sanitize_aux_ch(struct intel_bios_encoder_data *devdata,
-			    enum port port)
-{
-	struct drm_i915_private *i915 = devdata->i915;
-	struct child_device_config *child;
-	enum port p;
-
-	p = get_port_by_aux_ch(i915, devdata->child.aux_channel);
-	if (p == PORT_NONE)
-		return;
-
-	drm_dbg_kms(&i915->drm,
-		    "port %c trying to use the same AUX CH (0x%x) as port %c, "
-		    "disabling port %c DP support\n",
-		    port_name(port), devdata->child.aux_channel,
-		    port_name(p), port_name(p));
-
-	/*
-	 * If we have multiple ports supposedly sharing the aux channel, then DP
-	 * couldn't exist on the shared port. Otherwise they share the same aux
-	 * channel 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_DISPLAYPORT_OUTPUT;
-	child->aux_channel = 0;
-}
-
 static u8 dvo_port_type(u8 dvo_port)
 {
 	switch (dvo_port) {
@@ -2688,9 +2638,6 @@ static void parse_ddi_port(struct intel_bios_encoder_data *devdata)
 
 	sanitize_device_type(devdata, port);
 
-	if (intel_bios_encoder_supports_dp(devdata))
-		sanitize_aux_ch(devdata, port);
-
 	i915->display.vbt.ports[port] = devdata;
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 662b5ceef3c8..9e4e6482aa26 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4938,8 +4938,11 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	dig_port->dp.output_reg = INVALID_MMIO_REG;
 	dig_port->max_lanes = intel_ddi_max_lanes(dig_port);
 
-	if (need_aux_ch(encoder, init_dp))
+	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 =
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
index 21b50a5c8a85..2d173bd495a3 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
@@ -792,25 +792,60 @@ static enum aux_ch default_aux_ch(struct intel_encoder *encoder)
 	return (enum aux_ch)encoder->port;
 }
 
+static struct intel_encoder *
+get_encoder_by_aux_ch(struct intel_encoder *encoder,
+		      enum aux_ch aux_ch)
+{
+	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)->aux_ch == aux_ch)
+			return other;
+	}
+
+	return NULL;
+}
+
 enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	struct intel_encoder *other;
+	const char *source;
 	enum aux_ch aux_ch;
 
 	aux_ch = intel_bios_dp_aux_ch(encoder->devdata);
-	if (aux_ch != AUX_CH_NONE) {
-		drm_dbg_kms(&i915->drm, "[ENCODER:%d:%s] using AUX %c (VBT)\n",
-			    encoder->base.base.id, encoder->base.name,
-			    aux_ch_name(aux_ch));
-		return aux_ch;
+	source = "VBT";
+
+	if (aux_ch == AUX_CH_NONE) {
+		aux_ch = default_aux_ch(encoder);
+		source = "platform default";
 	}
 
-	aux_ch = default_aux_ch(encoder);
+	if (aux_ch == AUX_CH_NONE)
+		return AUX_CH_NONE;
+
+	/* FIXME validate aux_ch against platform caps */
+
+	other = get_encoder_by_aux_ch(encoder, aux_ch);
+	if (other) {
+		drm_dbg_kms(&i915->drm,
+			    "[ENCODER:%d:%s] AUX CH %c already claimed by [ENCODER:%d:%s]\n",
+			    encoder->base.base.id, encoder->base.name, aux_ch_name(aux_ch),
+			    other->base.base.id, other->base.name);
+		return AUX_CH_NONE;
+	}
 
 	drm_dbg_kms(&i915->drm,
-		    "[ENCODER:%d:%s] using AUX %c (platform default)\n",
+		    "[ENCODER:%d:%s] Using AUX CH %c (%s)\n",
 		    encoder->base.base.id, encoder->base.name,
-		    aux_ch_name(aux_ch));
+		    aux_ch_name(aux_ch), source);
 
 	return aux_ch;
 }