drm/amd/display: Add stream creation tests for connector

Add KUnit coverage for create_stream_for_sink(): fake sink success,
dm context setup, virtual signal handling, scaling source, and reuse
of an existing sink.

Assisted-by: Copilot:Claude-Opus-4.8
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1383,7 +1383,7 @@ static void apply_dsc_policy_for_stream(struct amdgpu_dm_connector *aconnector,
 }
 #endif
 
-static struct dc_stream_state *
+STATIC_IFN_KUNIT struct dc_stream_state *
 create_stream_for_sink(struct drm_connector *connector,
 		       const struct drm_display_mode *drm_mode,
 		       const struct dm_connector_state *dm_state,
@@ -1567,6 +1567,7 @@ create_stream_for_sink(struct drm_connector *connector,
 
 	return stream;
 }
+EXPORT_IF_KUNIT(create_stream_for_sink);
 
 /**
  * amdgpu_dm_connector_poll - Poll a connector to see if it's connected to a display

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.h

@@ -158,6 +158,12 @@ void fill_stream_properties_from_drm_display_mode(
 	const struct drm_connector_state *connector_state,
 	const struct dc_stream_state *old_stream,
 	int requested_bpc);
+struct dc_stream_state *
+create_stream_for_sink(struct drm_connector *connector,
+		       const struct drm_display_mode *drm_mode,
+		       const struct dm_connector_state *dm_state,
+		       const struct dc_stream_state *old_stream,
+		       int requested_bpc);
 enum display_content_type
 get_output_content_type(const struct drm_connector_state *connector_state);
 bool adjust_colour_depth_from_display_info(struct dc_crtc_timing *timing_out,

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

@@ -3604,6 +3604,176 @@ static void dm_test_fill_stream_aspect_ratio(struct kunit *test)
 			(int)ASPECT_RATIO_16_9);
 }
 
+/* Tests for create_stream_for_sink() */
+
+/*
+ * Build the inputs for create_stream_for_sink(). The connector is registered
+ * against a real kunit drm_device so that to_amdgpu_dm_connector() and the drm
+ * debug helpers resolve. The DC link carries a zeroed dc_context so that
+ * dc_create_stream_for_sink() can allocate and construct a stream.
+ *
+ * By default no dc_sink is attached, so create_stream_for_sink() builds a fake
+ * VIRTUAL sink. The VIRTUAL signal keeps the DSC, audio and DP/HDMI infoframe
+ * paths as no-ops, making the exercised behaviour deterministic.
+ */
+struct dm_test_stream_ctx {
+	struct drm_device *drm;
+	struct amdgpu_dm_connector *aconnector;
+	struct dc_context *dc_ctx;
+	struct dc_link *link;
+	struct dm_connector_state *dm_state;
+	struct drm_display_mode *mode;
+};
+
+static struct dm_test_stream_ctx *dm_test_stream_ctx_alloc(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx;
+	struct device *dev;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx);
+
+	dev = drm_kunit_helper_alloc_device(test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
+
+	ctx->drm = __drm_kunit_helper_alloc_drm_device(test, dev,
+						       sizeof(*ctx->drm), 0,
+						       DRIVER_MODESET);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->drm);
+
+	ctx->aconnector = kunit_kzalloc(test, sizeof(*ctx->aconnector), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx->aconnector);
+	KUNIT_ASSERT_EQ(test,
+		drmm_connector_init(ctx->drm, &ctx->aconnector->base,
+				    &dm_test_connector_funcs,
+				    DRM_MODE_CONNECTOR_DisplayPort, NULL), 0);
+
+	ctx->dc_ctx = kunit_kzalloc(test, sizeof(*ctx->dc_ctx), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx->dc_ctx);
+
+	ctx->link = kunit_kzalloc(test, sizeof(*ctx->link), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx->link);
+	ctx->link->ctx = ctx->dc_ctx;
+	ctx->link->connector_signal = SIGNAL_TYPE_DISPLAY_PORT;
+
+	ctx->aconnector->dc_link = ctx->link;
+	ctx->aconnector->dc_sink = NULL;
+
+	ctx->dm_state = kunit_kzalloc(test, sizeof(*ctx->dm_state), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx->dm_state);
+	ctx->dm_state->scaling = RMX_OFF;
+
+	ctx->mode = kunit_kzalloc(test, sizeof(*ctx->mode), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx->mode);
+	ctx->mode->hdisplay = 1920;
+	ctx->mode->vdisplay = 1080;
+	ctx->mode->clock = 148500;
+
+	return ctx;
+}
+
+/**
+ * dm_test_create_stream_fake_sink_success - Test a stream is built from a fake sink
+ * @test: The KUnit test context
+ */
+static void dm_test_create_stream_fake_sink_success(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx = dm_test_stream_ctx_alloc(test);
+	struct dc_stream_state *stream;
+
+	stream = create_stream_for_sink(&ctx->aconnector->base, ctx->mode,
+					ctx->dm_state, NULL, 8);
+
+	KUNIT_ASSERT_NOT_NULL(test, stream);
+	dc_stream_release(stream);
+}
+
+/**
+ * dm_test_create_stream_sets_dm_context - Test dm_stream_context points to aconnector
+ * @test: The KUnit test context
+ */
+static void dm_test_create_stream_sets_dm_context(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx = dm_test_stream_ctx_alloc(test);
+	struct dc_stream_state *stream;
+
+	stream = create_stream_for_sink(&ctx->aconnector->base, ctx->mode,
+					ctx->dm_state, NULL, 8);
+
+	KUNIT_ASSERT_NOT_NULL(test, stream);
+	KUNIT_EXPECT_PTR_EQ(test, stream->dm_stream_context, ctx->aconnector);
+	dc_stream_release(stream);
+}
+
+/**
+ * dm_test_create_stream_virtual_signal - Test the fake sink yields a VIRTUAL signal
+ * @test: The KUnit test context
+ */
+static void dm_test_create_stream_virtual_signal(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx = dm_test_stream_ctx_alloc(test);
+	struct dc_stream_state *stream;
+
+	stream = create_stream_for_sink(&ctx->aconnector->base, ctx->mode,
+					ctx->dm_state, NULL, 8);
+
+	KUNIT_ASSERT_NOT_NULL(test, stream);
+	KUNIT_EXPECT_EQ(test, (int)stream->signal, (int)SIGNAL_TYPE_VIRTUAL);
+	dc_stream_release(stream);
+}
+
+/**
+ * dm_test_create_stream_scaling_src - Test the source rect follows the mode
+ * @test: The KUnit test context
+ *
+ * With scaling off the full-screen source viewport matches the requested mode.
+ */
+static void dm_test_create_stream_scaling_src(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx = dm_test_stream_ctx_alloc(test);
+	struct dc_stream_state *stream;
+
+	stream = create_stream_for_sink(&ctx->aconnector->base, ctx->mode,
+					ctx->dm_state, NULL, 8);
+
+	KUNIT_ASSERT_NOT_NULL(test, stream);
+	KUNIT_EXPECT_EQ(test, (int)stream->src.width, 1920);
+	KUNIT_EXPECT_EQ(test, (int)stream->src.height, 1080);
+	dc_stream_release(stream);
+}
+
+/**
+ * dm_test_create_stream_existing_sink - Test the existing-sink retain path
+ * @test: The KUnit test context
+ *
+ * When the connector already has a dc_sink, create_stream_for_sink() reuses it
+ * instead of building a fake sink.
+ */
+static void dm_test_create_stream_existing_sink(struct kunit *test)
+{
+	struct dm_test_stream_ctx *ctx = dm_test_stream_ctx_alloc(test);
+	struct dc_sink_init_data sink_init = { 0 };
+	struct dc_stream_state *stream;
+	struct dc_sink *sink;
+
+	sink_init.link = ctx->link;
+	sink_init.sink_signal = SIGNAL_TYPE_VIRTUAL;
+	sink = dc_sink_create(&sink_init);
+	KUNIT_ASSERT_NOT_NULL(test, sink);
+	sink->sink_signal = SIGNAL_TYPE_VIRTUAL;
+
+	ctx->aconnector->dc_sink = sink;
+
+	stream = create_stream_for_sink(&ctx->aconnector->base, ctx->mode,
+					ctx->dm_state, NULL, 8);
+
+	KUNIT_ASSERT_NOT_NULL(test, stream);
+	KUNIT_EXPECT_PTR_EQ(test, stream->sink, sink);
+
+	dc_stream_release(stream);
+	dc_sink_release(sink);
+}
+
 static struct kunit_case amdgpu_dm_connector_tests[] = {
 	/* get_subconnector_type */
 	KUNIT_CASE(dm_test_subconnector_type_none),
@@ -3798,6 +3968,12 @@ static struct kunit_case amdgpu_dm_connector_tests[] = {
 	KUNIT_CASE(dm_test_fill_stream_color_depth_requested_bpc),
 	KUNIT_CASE(dm_test_fill_stream_content_type),
 	KUNIT_CASE(dm_test_fill_stream_aspect_ratio),
+	/* create_stream_for_sink */
+	KUNIT_CASE(dm_test_create_stream_fake_sink_success),
+	KUNIT_CASE(dm_test_create_stream_sets_dm_context),
+	KUNIT_CASE(dm_test_create_stream_virtual_signal),
+	KUNIT_CASE(dm_test_create_stream_scaling_src),
+	KUNIT_CASE(dm_test_create_stream_existing_sink),
 	{}
 };
 

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

@@ -73,6 +73,7 @@ void dc_sink_release(struct dc_sink *sink)
 {
 	kref_put(&sink->refcount, dc_sink_free);
 }
+EXPORT_IF_KUNIT(dc_sink_release);
 
 struct dc_sink *dc_sink_create(const struct dc_sink_init_data *init_params)
 {
@@ -94,6 +95,7 @@ struct dc_sink *dc_sink_create(const struct dc_sink_init_data *init_params)
 alloc_fail:
 	return NULL;
 }
+EXPORT_IF_KUNIT(dc_sink_create);
 
 /*******************************************************************************
  * Protected functions - visible only inside of DC (not visible in DM)

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

@@ -24,6 +24,7 @@
  */
 
 #include "dm_services.h"
+#include "dm_helpers.h"
 #include "basics/dc_common.h"
 #include "dc.h"
 #include "core_types.h"
@@ -203,6 +204,7 @@ void dc_stream_release(struct dc_stream_state *stream)
 		kref_put(&stream->refcount, dc_stream_free);
 	}
 }
+EXPORT_IF_KUNIT(dc_stream_release);
 
 struct dc_stream_state *dc_create_stream_for_sink(
 		struct dc_sink *sink)