drm/amd/display: USB-C to HDMI dongle not light

RV1 support only USB-C active DP-2-HDMI dongle. HPD short pulse is
generated only for DP signal.

When processing HPD short pulse, it must be DP active dongle. No need
for I2C-Over-AUX detection.

v2: Add description

Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -639,7 +639,7 @@ int amdgpu_dm_display_resume(struct amdgpu_device *adev )
 			continue;
 
 		mutex_lock(&aconnector->hpd_lock);
-		dc_link_detect(aconnector->dc_link, false);
+		dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD);
 		aconnector->dc_sink = NULL;
 		amdgpu_dm_update_connector_after_detect(aconnector);
 		mutex_unlock(&aconnector->hpd_lock);
@@ -855,7 +855,7 @@ static void handle_hpd_irq(void *param)
 	 * since (for MST case) MST does this in it's own context.
 	 */
 	mutex_lock(&aconnector->hpd_lock);
-	if (dc_link_detect(aconnector->dc_link, false)) {
+	if (dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD)) {
 		amdgpu_dm_update_connector_after_detect(aconnector);
 
 
@@ -965,7 +965,7 @@ static void handle_hpd_rx_irq(void *param)
 	if (dc_link_handle_hpd_rx_irq(aconnector->dc_link, NULL) &&
 			!is_mst_root_connector) {
 		/* Downstream Port status changed. */
-		if (dc_link_detect(aconnector->dc_link, false)) {
+		if (dc_link_detect(aconnector->dc_link, DETECT_REASON_HPDRX)) {
 			amdgpu_dm_update_connector_after_detect(aconnector);
 
 
@@ -1353,7 +1353,8 @@ int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 			goto fail_free_encoder;
 		}
 
-		if (dc_link_detect(dc_get_link_at_index(dm->dc, i), true))
+		if (dc_link_detect(dc_get_link_at_index(dm->dc, i),
+				DETECT_REASON_BOOT))
 			amdgpu_dm_update_connector_after_detect(aconnector);
 	}
 

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -355,7 +355,9 @@ static bool is_dp_sink_present(struct dc_link *link)
  * @brief
  * Detect output sink type
  */
-static enum signal_type link_detect_sink(struct dc_link *link)
+static enum signal_type link_detect_sink(
+	struct dc_link *link,
+	enum dc_detect_reason reason)
 {
 	enum signal_type result = get_basic_signal_type(
 		link->link_enc->id, link->link_id);
@@ -388,12 +390,17 @@ static enum signal_type link_detect_sink(struct dc_link *link)
 	}
 	break;
 	case CONNECTOR_ID_DISPLAY_PORT: {
-
-		/* Check whether DP signal detected: if not -
-		 * we assume signal is DVI; it could be corrected
-		 * to HDMI after dongle detection */
-		if (!is_dp_sink_present(link))
-			result = SIGNAL_TYPE_DVI_SINGLE_LINK;
+		/* DP HPD short pulse. Passive DP dongle will not
+		 * have short pulse
+		 */
+		if (reason != DETECT_REASON_HPDRX) {
+			/* Check whether DP signal detected: if not -
+			 * we assume signal is DVI; it could be corrected
+			 * to HDMI after dongle detection
+			 */
+			if (!is_dp_sink_present(link))
+				result = SIGNAL_TYPE_DVI_SINGLE_LINK;
+		}
 	}
 	break;
 	default:
@@ -460,9 +467,10 @@ static void detect_dp(
 	struct display_sink_capability *sink_caps,
 	bool *converter_disable_audio,
 	struct audio_support *audio_support,
-	bool boot)
+	enum dc_detect_reason reason)
 {
-	sink_caps->signal = link_detect_sink(link);
+	bool boot = false;
+	sink_caps->signal = link_detect_sink(link, reason);
 	sink_caps->transaction_type =
 		get_ddc_transaction_type(sink_caps->signal);
 
@@ -513,6 +521,8 @@ static void detect_dp(
 			 * Need check ->sink usages in case ->sink = NULL
 			 * TODO: s3 resume check
 			 */
+			if (reason == DETECT_REASON_BOOT)
+				boot = true;
 
 			if (dm_helpers_dp_mst_start_top_mgr(
 				link->ctx,
@@ -531,7 +541,7 @@ static void detect_dp(
 	}
 }
 
-bool dc_link_detect(struct dc_link *link, bool boot)
+bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 {
 	struct dc_sink_init_data sink_init_data = { 0 };
 	struct display_sink_capability sink_caps = { 0 };
@@ -596,7 +606,7 @@ bool dc_link_detect(struct dc_link *link, bool boot)
 				link,
 				&sink_caps,
 				&converter_disable_audio,
-				aud_support, boot);
+				aud_support, reason);
 
 			/* Active dongle downstream unplug */
 			if (link->type == dc_connection_active_dongle

drivers/gpu/drm/amd/display/dc/dc.h

@@ -885,7 +885,13 @@ bool dc_link_setup_psr(struct dc_link *dc_link,
  * true otherwise. True meaning further action is required (status update
  * and OS notification).
  */
-bool dc_link_detect(struct dc_link *dc_link, bool boot);
+enum dc_detect_reason {
+	DETECT_REASON_BOOT,
+	DETECT_REASON_HPD,
+	DETECT_REASON_HPDRX,
+};
+
+bool dc_link_detect(struct dc_link *dc_link, enum dc_detect_reason reason);
 
 /* Notify DC about DP RX Interrupt (aka Short Pulse Interrupt).
  * Return: