drm/amd/display: Fix Edid emulation for linux

[Why]
EDID emulation didn't work properly for linux, as we stop programming
if nothing is connected physically.

[How]
We get a flag from DRM when we want to do edid emulation. We check if
this flag is true and nothing is connected physically, if so we only
program the front end using VIRTUAL_SIGNAL.
Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -641,6 +641,87 @@ amdgpu_dm_find_first_crtc_matching_connector(struct drm_atomic_state *state,
 	return NULL;
 }
 
+static void emulated_link_detect(struct dc_link *link)
+{
+	struct dc_sink_init_data sink_init_data = { 0 };
+	struct display_sink_capability sink_caps = { 0 };
+	enum dc_edid_status edid_status;
+	struct dc_context *dc_ctx = link->ctx;
+	struct dc_sink *sink = NULL;
+	struct dc_sink *prev_sink = NULL;
+
+	link->type = dc_connection_none;
+	prev_sink = link->local_sink;
+
+	if (prev_sink != NULL)
+		dc_sink_retain(prev_sink);
+
+	switch (link->connector_signal) {
+	case SIGNAL_TYPE_HDMI_TYPE_A: {
+		sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
+		sink_caps.signal = SIGNAL_TYPE_HDMI_TYPE_A;
+		break;
+	}
+
+	case SIGNAL_TYPE_DVI_SINGLE_LINK: {
+		sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
+		sink_caps.signal = SIGNAL_TYPE_DVI_SINGLE_LINK;
+		break;
+	}
+
+	case SIGNAL_TYPE_DVI_DUAL_LINK: {
+		sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
+		sink_caps.signal = SIGNAL_TYPE_DVI_DUAL_LINK;
+		break;
+	}
+
+	case SIGNAL_TYPE_LVDS: {
+		sink_caps.transaction_type = DDC_TRANSACTION_TYPE_I2C;
+		sink_caps.signal = SIGNAL_TYPE_LVDS;
+		break;
+	}
+
+	case SIGNAL_TYPE_EDP: {
+		sink_caps.transaction_type =
+			DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
+		sink_caps.signal = SIGNAL_TYPE_EDP;
+		break;
+	}
+
+	case SIGNAL_TYPE_DISPLAY_PORT: {
+		sink_caps.transaction_type =
+			DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
+		sink_caps.signal = SIGNAL_TYPE_VIRTUAL;
+		break;
+	}
+
+	default:
+		DC_ERROR("Invalid connector type! signal:%d\n",
+			link->connector_signal);
+		return;
+	}
+
+	sink_init_data.link = link;
+	sink_init_data.sink_signal = sink_caps.signal;
+
+	sink = dc_sink_create(&sink_init_data);
+	if (!sink) {
+		DC_ERROR("Failed to create sink!\n");
+		return;
+	}
+
+	link->local_sink = sink;
+
+	edid_status = dm_helpers_read_local_edid(
+			link->ctx,
+			link,
+			sink);
+
+	if (edid_status != EDID_OK)
+		DC_ERROR("Failed to read EDID");
+
+}
+
 static int dm_resume(void *handle)
 {
 	struct amdgpu_device *adev = handle;
@@ -654,6 +735,7 @@ static int dm_resume(void *handle)
 	struct drm_plane *plane;
 	struct drm_plane_state *new_plane_state;
 	struct dm_plane_state *dm_new_plane_state;
+	enum dc_connection_type new_connection_type = dc_connection_none;
 	int ret;
 	int i;
 
@@ -684,6 +766,12 @@ static int dm_resume(void *handle)
 			continue;
 
 		mutex_lock(&aconnector->hpd_lock);
+		if (!dc_link_detect_sink(aconnector->dc_link, &new_connection_type))
+			DRM_ERROR("KMS: Failed to detect connector\n");
+
+		if (aconnector->base.force && new_connection_type == dc_connection_none)
+			emulated_link_detect(aconnector->dc_link);
+		else
 			dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD);
 
 		if (aconnector->fake_enable && aconnector->dc_link->local_sink)
@@ -922,6 +1010,7 @@ static void handle_hpd_irq(void *param)
 	struct amdgpu_dm_connector *aconnector = (struct amdgpu_dm_connector *)param;
 	struct drm_connector *connector = &aconnector->base;
 	struct drm_device *dev = connector->dev;
+	enum dc_connection_type new_connection_type = dc_connection_none;
 
 	/* In case of failure or MST no need to update connector status or notify the OS
 	 * since (for MST case) MST does this in it's own context.
@@ -931,7 +1020,21 @@ static void handle_hpd_irq(void *param)
 	if (aconnector->fake_enable)
 		aconnector->fake_enable = false;
 
-	if (dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD)) {
+	if (!dc_link_detect_sink(aconnector->dc_link, &new_connection_type))
+		DRM_ERROR("KMS: Failed to detect connector\n");
+
+	if (aconnector->base.force && new_connection_type == dc_connection_none) {
+		emulated_link_detect(aconnector->dc_link);
+
+
+		drm_modeset_lock_all(dev);
+		dm_restore_drm_connector_state(dev, connector);
+		drm_modeset_unlock_all(dev);
+
+		if (aconnector->base.force == DRM_FORCE_UNSPECIFIED)
+			drm_kms_helper_hotplug_event(dev);
+
+	} else if (dc_link_detect(aconnector->dc_link, DETECT_REASON_HPD)) {
 		amdgpu_dm_update_connector_after_detect(aconnector);
 
 
@@ -1031,6 +1134,7 @@ static void handle_hpd_rx_irq(void *param)
 	struct drm_device *dev = connector->dev;
 	struct dc_link *dc_link = aconnector->dc_link;
 	bool is_mst_root_connector = aconnector->mst_mgr.mst_state;
+	enum dc_connection_type new_connection_type = dc_connection_none;
 
 	/* TODO:Temporary add mutex to protect hpd interrupt not have a gpio
 	 * conflict, after implement i2c helper, this mutex should be
@@ -1042,7 +1146,24 @@ static void handle_hpd_rx_irq(void *param)
 	if (dc_link_handle_hpd_rx_irq(dc_link, NULL, NULL) &&
 			!is_mst_root_connector) {
 		/* Downstream Port status changed. */
-		if (dc_link_detect(dc_link, DETECT_REASON_HPDRX)) {
+		if (!dc_link_detect_sink(dc_link, &new_connection_type))
+			DRM_ERROR("KMS: Failed to detect connector\n");
+
+		if (aconnector->base.force && new_connection_type == dc_connection_none) {
+			emulated_link_detect(dc_link);
+
+			if (aconnector->fake_enable)
+				aconnector->fake_enable = false;
+
+			amdgpu_dm_update_connector_after_detect(aconnector);
+
+
+			drm_modeset_lock_all(dev);
+			dm_restore_drm_connector_state(dev, connector);
+			drm_modeset_unlock_all(dev);
+
+			drm_kms_helper_hotplug_event(dev);
+		} else if (dc_link_detect(dc_link, DETECT_REASON_HPDRX)) {
 
 			if (aconnector->fake_enable)
 				aconnector->fake_enable = false;
@@ -1433,6 +1554,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 	struct amdgpu_mode_info *mode_info = &adev->mode_info;
 	uint32_t link_cnt;
 	int32_t total_overlay_planes, total_primary_planes;
+	enum dc_connection_type new_connection_type = dc_connection_none;
 
 	link_cnt = dm->dc->caps.max_links;
 	if (amdgpu_dm_mode_config_init(dm->adev)) {
@@ -1499,7 +1621,14 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 
 		link = dc_get_link_at_index(dm->dc, i);
 
-		if (dc_link_detect(link, DETECT_REASON_BOOT)) {
+		if (!dc_link_detect_sink(link, &new_connection_type))
+			DRM_ERROR("KMS: Failed to detect connector\n");
+
+		if (aconnector->base.force && new_connection_type == dc_connection_none) {
+			emulated_link_detect(link);
+			amdgpu_dm_update_connector_after_detect(aconnector);
+
+		} else if (dc_link_detect(link, DETECT_REASON_BOOT)) {
 			amdgpu_dm_update_connector_after_detect(aconnector);
 			register_backlight_device(dm, link);
 		}
@@ -2494,7 +2623,7 @@ create_stream_for_sink(struct amdgpu_dm_connector *aconnector,
 	if (dm_state && dm_state->freesync_capable)
 		stream->ignore_msa_timing_param = true;
 finish:
-	if (sink && sink->sink_signal == SIGNAL_TYPE_VIRTUAL)
+	if (sink && sink->sink_signal == SIGNAL_TYPE_VIRTUAL && aconnector->base.force != DRM_FORCE_ON)
 		dc_sink_release(sink);
 
 	return stream;

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

@@ -195,7 +195,7 @@ static bool program_hpd_filter(
 	return result;
 }
 
-static bool detect_sink(struct dc_link *link, enum dc_connection_type *type)
+bool dc_link_detect_sink(struct dc_link *link, enum dc_connection_type *type)
 {
 	uint32_t is_hpd_high = 0;
 	struct gpio *hpd_pin;
@@ -604,7 +604,7 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 	if (link->connector_signal == SIGNAL_TYPE_VIRTUAL)
 		return false;
 
-	if (false == detect_sink(link, &new_connection_type)) {
+	if (false == dc_link_detect_sink(link, &new_connection_type)) {
 		BREAK_TO_DEBUGGER();
 		return false;
 	}

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

@@ -215,6 +215,7 @@ void dc_link_enable_hpd_filter(struct dc_link *link, bool enable);
 
 bool dc_link_is_dp_sink_present(struct dc_link *link);
 
+bool dc_link_detect_sink(struct dc_link *link, enum dc_connection_type *type);
 /*
  * DPCD access interfaces
  */