[PATCH v3 15/15] drm/tests: hdmi: Add test for unsuccessful forced fallback to YUV420
From: Cristian Ciocaltea
Date: Wed Mar 26 2025 - 06:23:35 EST
Provide test to verify a forced fallback to YUV420 output cannot succeed
when driver doesn't advertise YUV420 support.
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
---
drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 46 ++++++++++++++++++++++
1 file changed, 46 insertions(+)
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 99bedb2d6f555b3b140256000dfa7491d2a8f515..c2976b42aa2aacd2a68a871bffe97e795ca713d4 100644
--- a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
@@ -1493,6 +1493,51 @@ static void drm_test_check_max_tmds_rate_format_fallback_yuv420(struct kunit *te
drm_modeset_acquire_fini(&ctx);
}
+/*
+ * Test that if a driver supports only RGB, but the chosen mode can be
+ * supported by the screen only in YUV420 output format, we end up with
+ * an unsuccessful forced fallback attempt.
+ */
+static void drm_test_check_driver_unsupported_fallback_yuv420(struct kunit *test)
+{
+ struct drm_atomic_helper_connector_hdmi_priv *priv;
+ struct drm_modeset_acquire_ctx ctx;
+ struct drm_display_info *info;
+ struct drm_display_mode *yuv420_only_mode;
+ struct drm_connector *conn;
+ struct drm_device *drm;
+ struct drm_crtc *crtc;
+ int ret;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid(test,
+ BIT(HDMI_COLORSPACE_RGB),
+ 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_FALSE(test, conn->ycbcr_420_allowed);
+
+ 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));
+
+ drm_modeset_acquire_init(&ctx, 0);
+
+ ret = drm_kunit_helper_enable_crtc_connector(test, drm,
+ crtc, conn,
+ yuv420_only_mode,
+ &ctx);
+ KUNIT_EXPECT_LT(test, ret, 0);
+
+ 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
@@ -1884,6 +1929,7 @@ static struct kunit_case drm_atomic_helper_connector_hdmi_check_tests[] = {
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_driver_unsupported_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),
--
2.49.0