diff --git a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
index 1df12c0b7768e4f85f4c943840d9b4dcb6e079e0..77da5b88c4cbd5bba22f4f0ce1ef2928042d7d50 100644
--- a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
@@ -1223,7 +1223,7 @@ static void drm_test_check_hdmi_funcs_reject_rate(struct kunit *test)
  * Then we will pick the latter, and the computed TMDS character rate
  * will be equal to 1.25 times the mode pixel clock.
  */
-static void drm_test_check_max_tmds_rate_bpc_fallback(struct kunit *test)
+static void drm_test_check_max_tmds_rate_bpc_fallback_rgb(struct kunit *test)
 {
 	struct drm_atomic_helper_connector_hdmi_priv *priv;
 	struct drm_modeset_acquire_ctx ctx;
@@ -1275,6 +1275,72 @@ static void drm_test_check_max_tmds_rate_bpc_fallback(struct kunit *test)
 	drm_modeset_acquire_fini(&ctx);
 }
 
+/*
+ * Test that if:
+ * - We have an HDMI connector supporting both RGB and YUV420
+ * - The chosen mode can be supported in YUV420 output format only
+ * - The chosen mode has a TMDS character rate higher than the display
+ *   supports in YUV420/12bpc
+ * - The chosen mode has a TMDS character rate lower than the display
+ *   supports in YUV420/10bpc.
+ *
+ * Then we will pick the latter, and the computed TMDS character rate
+ * will be equal to 1.25 * 0.5 times the mode pixel clock.
+ */
+static void drm_test_check_max_tmds_rate_bpc_fallback_yuv420(struct kunit *test)
+{
+	struct drm_atomic_helper_connector_hdmi_priv *priv;
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_connector_state *conn_state;
+	struct drm_display_info *info;
+	struct drm_display_mode *yuv420_only_mode;
+	unsigned long long rate;
+	struct drm_connector *conn;
+	struct drm_device *drm;
+	struct drm_crtc *crtc;
+	int ret;
+
+	priv = drm_kunit_helper_connector_hdmi_init_set_edid(test,
+				BIT(HDMI_COLORSPACE_RGB) |
+				BIT(HDMI_COLORSPACE_YUV420),
+				12,
+				test_edid_hdmi_1080p_rgb_yuv_4k_yuv420_dc_max_200mhz);
+	KUNIT_ASSERT_NOT_NULL(test, priv);
+
+	drm = &priv->drm;
+	crtc = priv->crtc;
+	conn = &priv->connector;
+	info = &conn->display_info;
+	KUNIT_ASSERT_TRUE(test, info->is_hdmi);
+	KUNIT_ASSERT_GT(test, info->max_tmds_clock, 0);
+
+	yuv420_only_mode = drm_kunit_display_mode_from_cea_vic(test, drm, 95);
+	KUNIT_ASSERT_NOT_NULL(test, yuv420_only_mode);
+	KUNIT_ASSERT_TRUE(test, drm_mode_is_420_only(info, yuv420_only_mode));
+
+	rate = drm_hdmi_compute_mode_clock(yuv420_only_mode, 12, HDMI_COLORSPACE_YUV420);
+	KUNIT_ASSERT_GT(test, rate, info->max_tmds_clock * 1000);
+
+	rate = drm_hdmi_compute_mode_clock(yuv420_only_mode, 10, HDMI_COLORSPACE_YUV420);
+	KUNIT_ASSERT_LT(test, rate, info->max_tmds_clock * 1000);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	ret = light_up_connector(test, drm, crtc, conn, yuv420_only_mode, &ctx);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	conn_state = conn->state;
+	KUNIT_ASSERT_NOT_NULL(test, conn_state);
+
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_bpc, 10);
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_format, HDMI_COLORSPACE_YUV420);
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.tmds_char_rate,
+			yuv420_only_mode->clock * 1250 * 0.5);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+}
+
 /*
  * Test that if:
  * - We have an HDMI connector supporting both RGB and YUV422 and up to
@@ -1288,7 +1354,7 @@ static void drm_test_check_max_tmds_rate_bpc_fallback(struct kunit *test)
  * Then we will prefer to keep the RGB format with a lower bpc over
  * picking YUV422.
  */
-static void drm_test_check_max_tmds_rate_format_fallback(struct kunit *test)
+static void drm_test_check_max_tmds_rate_format_fallback_yuv422(struct kunit *test)
 {
 	struct drm_atomic_helper_connector_hdmi_priv *priv;
 	struct drm_modeset_acquire_ctx ctx;
@@ -1344,6 +1410,75 @@ static void drm_test_check_max_tmds_rate_format_fallback(struct kunit *test)
 	drm_modeset_acquire_fini(&ctx);
 }
 
+/*
+ * Test that if:
+ * - We have an HDMI connector supporting both RGB and YUV420 and up to
+ *   12 bpc
+ * - The chosen mode has a TMDS character rate higher than the display
+ *   supports in RGB/10bpc but lower than the display supports in
+ *   RGB/8bpc
+ * - The chosen mode has a TMDS character rate lower than the display
+ *   supports in YUV420/12bpc.
+ *
+ * Then we will prefer to keep the RGB format with a lower bpc over
+ * picking YUV420.
+ */
+static void drm_test_check_max_tmds_rate_format_fallback_yuv420(struct kunit *test)
+{
+	struct drm_atomic_helper_connector_hdmi_priv *priv;
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_connector_state *conn_state;
+	struct drm_display_info *info;
+	struct drm_display_mode *preferred;
+	unsigned long long rate;
+	struct drm_connector *conn;
+	struct drm_device *drm;
+	struct drm_crtc *crtc;
+	int ret;
+
+	priv = drm_kunit_helper_connector_hdmi_init_set_edid(test,
+				BIT(HDMI_COLORSPACE_RGB) |
+				BIT(HDMI_COLORSPACE_YUV420),
+				12,
+				test_edid_hdmi_4k_rgb_yuv420_dc_max_340mhz);
+	KUNIT_ASSERT_NOT_NULL(test, priv);
+
+	drm = &priv->drm;
+	crtc = priv->crtc;
+	conn = &priv->connector;
+	info = &conn->display_info;
+	KUNIT_ASSERT_TRUE(test, info->is_hdmi);
+	KUNIT_ASSERT_GT(test, info->max_tmds_clock, 0);
+
+	preferred = find_preferred_mode(conn);
+	KUNIT_ASSERT_NOT_NULL(test, preferred);
+	KUNIT_ASSERT_FALSE(test, preferred->flags & DRM_MODE_FLAG_DBLCLK);
+	KUNIT_ASSERT_TRUE(test, drm_mode_is_420_also(info, preferred));
+
+	rate = drm_hdmi_compute_mode_clock(preferred, 8, HDMI_COLORSPACE_RGB);
+	KUNIT_ASSERT_LT(test, rate, info->max_tmds_clock * 1000);
+
+	rate = drm_hdmi_compute_mode_clock(preferred, 10, HDMI_COLORSPACE_RGB);
+	KUNIT_ASSERT_GT(test, rate, info->max_tmds_clock * 1000);
+
+	rate = drm_hdmi_compute_mode_clock(preferred, 12, HDMI_COLORSPACE_YUV420);
+	KUNIT_ASSERT_LT(test, rate, info->max_tmds_clock * 1000);
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	ret = light_up_connector(test, drm, crtc, conn, preferred, &ctx);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	conn_state = conn->state;
+	KUNIT_ASSERT_NOT_NULL(test, conn_state);
+
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_bpc, 8);
+	KUNIT_EXPECT_EQ(test, conn_state->hdmi.output_format, HDMI_COLORSPACE_RGB);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+}
+
 /*
  * Test that if a driver and screen supports RGB and YUV formats, and we
  * try to set the VIC 1 mode, we end up with 8bpc RGB even if we could
@@ -1713,8 +1848,10 @@ 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_disable_connector),
 	KUNIT_CASE(drm_test_check_hdmi_funcs_reject_rate),
-	KUNIT_CASE(drm_test_check_max_tmds_rate_bpc_fallback),
-	KUNIT_CASE(drm_test_check_max_tmds_rate_format_fallback),
+	KUNIT_CASE(drm_test_check_max_tmds_rate_bpc_fallback_rgb),
+	KUNIT_CASE(drm_test_check_max_tmds_rate_bpc_fallback_yuv420),
+	KUNIT_CASE(drm_test_check_max_tmds_rate_format_fallback_yuv422),
+	KUNIT_CASE(drm_test_check_max_tmds_rate_format_fallback_yuv420),
 	KUNIT_CASE(drm_test_check_output_bpc_crtc_mode_changed),
 	KUNIT_CASE(drm_test_check_output_bpc_crtc_mode_not_changed),
 	KUNIT_CASE(drm_test_check_output_bpc_dvi),
diff --git a/drivers/gpu/drm/tests/drm_kunit_edid.h b/drivers/gpu/drm/tests/drm_kunit_edid.h
index ff316e6114d65c96b1338cd83bc0d8d9e6e143e9..8e9086df20c690f34623d7858c716032d77d0c26 100644
--- a/drivers/gpu/drm/tests/drm_kunit_edid.h
+++ b/drivers/gpu/drm/tests/drm_kunit_edid.h
@@ -695,4 +695,114 @@ static const unsigned char test_edid_hdmi_1080p_rgb_yuv_4k_yuv420_dc_max_200mhz[
 	0x00, 0x00, 0x00, 0xca
 };
 
+/*
+ * edid-decode (hex):
+ *
+ * 00 ff ff ff ff ff ff 00 31 d8 34 00 00 00 00 00
+ * ff 23 01 03 80 60 36 78 0f ee 91 a3 54 4c 99 26
+ * 0f 50 54 20 00 00 01 01 01 01 01 01 01 01 01 01
+ * 01 01 01 01 01 01 04 74 00 30 f2 70 5a 80 b0 58
+ * 8a 00 40 84 63 00 00 1e 00 00 00 fc 00 54 65 73
+ * 74 20 45 44 49 44 0a 20 20 20 00 00 00 fd 00 18
+ * 55 18 5e 22 00 0a 20 20 20 20 20 20 00 00 00 10
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 ce
+ *
+ * 02 03 27 31 41 5f 6c 03 0c 00 10 00 78 44 20 00
+ * 00 01 03 6d d8 5d c4 01 44 80 07 00 00 00 00 00
+ * 00 e3 0f 01 00 e1 0e 00 00 00 00 00 00 00 00 00
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ * 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 84
+ *
+ * ----------------
+ *
+ * Block 0, Base EDID:
+ *   EDID Structure Version & Revision: 1.3
+ *   Vendor & Product Identification:
+ *     Manufacturer: LNX
+ *     Model: 52
+ *     Model year: 2025
+ *   Basic Display Parameters & Features:
+ *     Digital display
+ *     Maximum image size: 96 cm x 54 cm
+ *     Gamma: 2.20
+ *     RGB color display
+ *     Default (sRGB) color space is primary color space
+ *     First detailed timing is the preferred timing
+ *     Supports GTF timings within operating range
+ *   Color Characteristics:
+ *     Red  : 0.6396, 0.3300
+ *     Green: 0.2998, 0.5996
+ *     Blue : 0.1503, 0.0595
+ *     White: 0.3125, 0.3291
+ *   Established Timings I & II:
+ *     DMT 0x04:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
+ *   Standard Timings: none
+ *   Detailed Timing Descriptors:
+ *     DTD 1:  3840x2160   30.000000 Hz  16:9     67.500 kHz    297.000000 MHz (1600 mm x 900 mm)
+ *                  Hfront  176 Hsync  88 Hback  296 Hpol P
+ *                  Vfront    8 Vsync  10 Vback   72 Vpol P
+ *     Display Product Name: 'Test EDID'
+ *     Display Range Limits:
+ *       Monitor ranges (GTF): 24-85 Hz V, 24-94 kHz H, max dotclock 340 MHz
+ *     Dummy Descriptor:
+ *   Extension blocks: 1
+ * Checksum: 0xce
+ *
+ * ----------------
+ *
+ * Block 1, CTA-861 Extension Block:
+ *   Revision: 3
+ *   Supports YCbCr 4:4:4
+ *   Supports YCbCr 4:2:2
+ *   Native detailed modes: 1
+ *   Video Data Block:
+ *     VIC  95:  3840x2160   30.000000 Hz  16:9     67.500 kHz    297.000000 MHz
+ *   Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
+ *     Source physical address: 1.0.0.0
+ *     DC_48bit
+ *     DC_36bit
+ *     DC_30bit
+ *     DC_Y444
+ *     Maximum TMDS clock: 340 MHz
+ *     Extended HDMI video details:
+ *   Vendor-Specific Data Block (HDMI Forum), OUI C4-5D-D8:
+ *     Version: 1
+ *     Maximum TMDS Character Rate: 340 MHz
+ *     SCDC Present
+ *     Supports 16-bits/component Deep Color 4:2:0 Pixel Encoding
+ *     Supports 12-bits/component Deep Color 4:2:0 Pixel Encoding
+ *     Supports 10-bits/component Deep Color 4:2:0 Pixel Encoding
+ *   YCbCr 4:2:0 Capability Map Data Block:
+ *     VIC  95:  3840x2160   30.000000 Hz  16:9     67.500 kHz    297.000000 MHz
+ *   YCbCr 4:2:0 Video Data Block:
+ * Checksum: 0x84
+ */
+static const unsigned char test_edid_hdmi_4k_rgb_yuv420_dc_max_340mhz[] = {
+	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x31, 0xd8, 0x34, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0xff, 0x23, 0x01, 0x03, 0x80, 0x60, 0x36, 0x78,
+	0x0f, 0xee, 0x91, 0xa3, 0x54, 0x4c, 0x99, 0x26, 0x0f, 0x50, 0x54, 0x20,
+	0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x04, 0x74, 0x00, 0x30, 0xf2, 0x70,
+	0x5a, 0x80, 0xb0, 0x58, 0x8a, 0x00, 0x40, 0x84, 0x63, 0x00, 0x00, 0x1e,
+	0x00, 0x00, 0x00, 0xfc, 0x00, 0x54, 0x65, 0x73, 0x74, 0x20, 0x45, 0x44,
+	0x49, 0x44, 0x0a, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x18,
+	0x55, 0x18, 0x5e, 0x22, 0x00, 0x0a, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+	0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xce, 0x02, 0x03, 0x27, 0x31,
+	0x41, 0x5f, 0x6c, 0x03, 0x0c, 0x00, 0x10, 0x00, 0x78, 0x44, 0x20, 0x00,
+	0x00, 0x01, 0x03, 0x6d, 0xd8, 0x5d, 0xc4, 0x01, 0x44, 0x80, 0x07, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xe3, 0x0f, 0x01, 0x00, 0xe1, 0x0e, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x84
+};
+
 #endif // DRM_KUNIT_EDID_H_
