diff --git a/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c b/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
index a5cba3e63f99..4e2ec436987b 100644
--- a/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_atomic_state_helper_test.c
@@ -824,6 +824,15 @@ static struct kunit_case drm_atomic_helper_connector_hdmi_check_tests[] = {
 	KUNIT_CASE(drm_test_check_broadcast_rgb_crtc_mode_not_changed),
 	KUNIT_CASE(drm_test_check_output_bpc_crtc_mode_changed),
 	KUNIT_CASE(drm_test_check_output_bpc_crtc_mode_not_changed),
+	/*
+	 * TODO: We should have tests to check that a change in the
+	 * format triggers a CRTC mode change just like we do for the
+	 * RGB Quantization and BPC.
+	 *
+	 * However, we don't have any way to control which format gets
+	 * picked up aside from changing the BPC or mode which would
+	 * already trigger a mode change.
+	 */
 	{ }
 };
 
@@ -924,11 +933,34 @@ static void drm_test_check_bpc_12_value(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_bpc, 0);
 }
 
+/*
+ * Test that the value of the output format property out of reset is set
+ * to RGB, even if the driver supports more than that.
+ */
+static void drm_test_check_format_value(struct kunit *test)
+{
+	struct drm_atomic_helper_connector_hdmi_priv *priv;
+	struct drm_connector_state *conn_state;
+	struct drm_connector *conn;
+
+	priv = drm_atomic_helper_connector_hdmi_init(test,
+						     BIT(HDMI_COLORSPACE_RGB) |
+						     BIT(HDMI_COLORSPACE_YUV422) |
+						     BIT(HDMI_COLORSPACE_YUV444),
+						     8);
+	KUNIT_ASSERT_NOT_NULL(test, priv);
+
+	conn = &priv->connector;
+	conn_state = conn->state;
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_format, HDMI_COLORSPACE_RGB);
+}
+
 static struct kunit_case drm_atomic_helper_connector_hdmi_reset_tests[] = {
 	KUNIT_CASE(drm_test_check_broadcast_rgb_value),
 	KUNIT_CASE(drm_test_check_bpc_8_value),
 	KUNIT_CASE(drm_test_check_bpc_10_value),
 	KUNIT_CASE(drm_test_check_bpc_12_value),
+	KUNIT_CASE(drm_test_check_format_value),
 	{ }
 };
 
diff --git a/drivers/gpu/drm/tests/drm_connector_test.c b/drivers/gpu/drm/tests/drm_connector_test.c
index 9c5ce7e81d01..fa6fe8084107 100644
--- a/drivers/gpu/drm/tests/drm_connector_test.c
+++ b/drivers/gpu/drm/tests/drm_connector_test.c
@@ -348,6 +348,42 @@ static void drm_test_connector_hdmi_init_bpc_12(struct kunit *test)
 	KUNIT_EXPECT_NOT_NULL(test, drm_mode_obj_find_prop_id(&connector->base, prop->base.id));
 }
 
+/*
+ * Test that the registration of an HDMI connector with no supported
+ * format fails.
+ */
+static void drm_test_connector_hdmi_init_formats_empty(struct kunit *test)
+{
+	struct drm_connector_init_priv *priv = test->priv;
+	int ret;
+
+	ret = drmm_connector_hdmi_init(&priv->drm, &priv->connector,
+				       &dummy_funcs,
+				       DRM_MODE_CONNECTOR_HDMIA,
+				       &priv->ddc,
+				       0,
+				       8);
+	KUNIT_EXPECT_LT(test, ret, 0);
+}
+
+/*
+ * Test that the registration of an HDMI connector not listing RGB as a
+ * supported format fails.
+ */
+static void drm_test_connector_hdmi_init_formats_no_rgb(struct kunit *test)
+{
+	struct drm_connector_init_priv *priv = test->priv;
+	int ret;
+
+	ret = drmm_connector_hdmi_init(&priv->drm, &priv->connector,
+				       &dummy_funcs,
+				       DRM_MODE_CONNECTOR_HDMIA,
+				       &priv->ddc,
+				       BIT(HDMI_COLORSPACE_YUV422),
+				       8);
+	KUNIT_EXPECT_LT(test, ret, 0);
+}
+
 /*
  * Test that the registration of an HDMI connector with an HDMI
  * connector type succeeds.
@@ -433,6 +469,8 @@ static struct kunit_case drmm_connector_hdmi_init_tests[] = {
 	KUNIT_CASE(drm_test_connector_hdmi_init_bpc_12),
 	KUNIT_CASE(drm_test_connector_hdmi_init_bpc_invalid),
 	KUNIT_CASE(drm_test_connector_hdmi_init_bpc_null),
+	KUNIT_CASE(drm_test_connector_hdmi_init_formats_empty),
+	KUNIT_CASE(drm_test_connector_hdmi_init_formats_no_rgb),
 	KUNIT_CASE(drm_test_connector_hdmi_init_null_ddc),
 	KUNIT_CASE_PARAM(drm_test_connector_hdmi_init_type_valid,
 			 drm_connector_hdmi_init_type_valid_gen_params),
@@ -567,6 +605,64 @@ static struct kunit_suite drm_hdmi_connector_get_broadcast_rgb_name_test_suite =
 	.test_cases = drm_hdmi_connector_get_broadcast_rgb_name_tests,
 };
 
+struct drm_hdmi_connector_get_output_format_name_test {
+	unsigned int kind;
+	const char *expected_name;
+};
+
+#define OUTPUT_FORMAT_TEST(_kind, _name)	\
+	{					\
+		.kind = _kind,			\
+		.expected_name = _name,		\
+	}
+
+static void drm_test_drm_hdmi_connector_get_output_format_name(struct kunit *test)
+{
+	const struct drm_hdmi_connector_get_output_format_name_test *params =
+		test->param_value;
+
+	KUNIT_EXPECT_STREQ(test,
+			   drm_hdmi_connector_get_output_format_name(params->kind),
+			   params->expected_name);
+}
+
+static const
+struct drm_hdmi_connector_get_output_format_name_test
+drm_hdmi_connector_get_output_format_name_valid_tests[] = {
+	OUTPUT_FORMAT_TEST(HDMI_COLORSPACE_RGB, "RGB"),
+	OUTPUT_FORMAT_TEST(HDMI_COLORSPACE_YUV420, "YUV 4:2:0"),
+	OUTPUT_FORMAT_TEST(HDMI_COLORSPACE_YUV422, "YUV 4:2:2"),
+	OUTPUT_FORMAT_TEST(HDMI_COLORSPACE_YUV444, "YUV 4:4:4"),
+};
+
+static void
+drm_hdmi_connector_get_output_format_name_valid_desc(const struct drm_hdmi_connector_get_output_format_name_test *t,
+						     char *desc)
+{
+	sprintf(desc, "%s", t->expected_name);
+}
+
+KUNIT_ARRAY_PARAM(drm_hdmi_connector_get_output_format_name_valid,
+		  drm_hdmi_connector_get_output_format_name_valid_tests,
+		  drm_hdmi_connector_get_output_format_name_valid_desc);
+
+static void drm_test_drm_hdmi_connector_get_output_format_name_invalid(struct kunit *test)
+{
+	KUNIT_EXPECT_NULL(test, drm_hdmi_connector_get_output_format_name(4));
+};
+
+static struct kunit_case drm_hdmi_connector_get_output_format_name_tests[] = {
+	KUNIT_CASE_PARAM(drm_test_drm_hdmi_connector_get_output_format_name,
+			 drm_hdmi_connector_get_output_format_name_valid_gen_params),
+	KUNIT_CASE(drm_test_drm_hdmi_connector_get_output_format_name_invalid),
+	{ }
+};
+
+static struct kunit_suite drm_hdmi_connector_get_output_format_name_test_suite = {
+	.name = "drm_hdmi_connector_get_output_format_name",
+	.test_cases = drm_hdmi_connector_get_output_format_name_tests,
+};
+
 static void drm_test_drm_connector_attach_broadcast_rgb_property(struct kunit *test)
 {
 	struct drm_connector_init_priv *priv = test->priv;
@@ -628,7 +724,8 @@ kunit_test_suites(
 	&drmm_connector_init_test_suite,
 	&drm_connector_attach_broadcast_rgb_property_test_suite,
 	&drm_get_tv_mode_from_name_test_suite,
-	&drm_hdmi_connector_get_broadcast_rgb_name_test_suite
+	&drm_hdmi_connector_get_broadcast_rgb_name_test_suite,
+	&drm_hdmi_connector_get_output_format_name_test_suite
 );
 
 MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
