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Message-Id: <20260121-color-format-v7-19-ef790dae780c@collabora.com>
Date: Wed, 21 Jan 2026 15:45:26 +0100
From: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
To: Harry Wentland <harry.wentland@....com>, Leo Li <sunpeng.li@....com>,
Rodrigo Siqueira <siqueira@...lia.com>,
Alex Deucher <alexander.deucher@....com>,
Christian König <christian.koenig@....com>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
Sandy Huang <hjc@...k-chips.com>,
Heiko Stübner <heiko@...ech.de>,
Andy Yan <andy.yan@...k-chips.com>,
Jani Nikula <jani.nikula@...ux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@...el.com>,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Tvrtko Ursulin <tursulin@...ulin.net>, Dmitry Baryshkov <lumag@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>, Rob Herring <robh@...nel.org>,
Jonathan Corbet <corbet@....net>
Cc: kernel@...labora.com, amd-gfx@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
intel-gfx@...ts.freedesktop.org, intel-xe@...ts.freedesktop.org,
linux-doc@...r.kernel.org,
Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Subject: [PATCH v7 19/22] drm/tests: hdmi: Add tests for HDMI helper's
mode_valid
Add some KUnit tests to verify that the HDMI state helper's mode_valid
implementation does not improperly reject chroma subsampled modes on the
basis of their clock rate not being satisfiable in RGB.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
---
drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 109 +++++++++++++++++++++
1 file changed, 109 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 f9648f9de46b..b2c421d7e986 100644
--- a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
@@ -77,6 +77,23 @@ static struct drm_display_mode *find_420_only_mode(struct drm_connector *connect
return NULL;
}
+static struct drm_display_mode *find_420_also_mode(struct drm_connector *connector)
+{
+ struct drm_device *drm = connector->dev;
+ struct drm_display_mode *mode;
+
+ mutex_lock(&drm->mode_config.mutex);
+ list_for_each_entry(mode, &connector->modes, head) {
+ if (drm_mode_is_420_also(&connector->display_info, mode)) {
+ mutex_unlock(&drm->mode_config.mutex);
+ return mode;
+ }
+ }
+ mutex_unlock(&drm->mode_config.mutex);
+
+ return NULL;
+}
+
static int set_connector_edid(struct kunit *test, struct drm_connector *connector,
const void *edid, size_t edid_len)
{
@@ -2700,11 +2717,103 @@ static void drm_test_check_mode_valid_reject_max_clock(struct kunit *test)
KUNIT_EXPECT_EQ(test, preferred->clock, 25200);
}
+/*
+ * Test that drm_hdmi_connector_mode_valid() will accept modes that require a
+ * 4:2:0 chroma subsampling, even if said mode would violate maximum clock
+ * constraints if it used RGB 4:4:4.
+ */
+static void drm_test_check_mode_valid_yuv420_only_max_clock(struct kunit *test)
+{
+ struct drm_atomic_helper_connector_hdmi_priv *priv;
+ struct drm_display_mode *dank;
+ struct drm_connector *conn;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(HDMI_COLORSPACE_RGB) |
+ BIT(HDMI_COLORSPACE_YUV420),
+ 8,
+ &dummy_connector_hdmi_funcs,
+ test_edid_hdmi_1080p_rgb_yuv_4k_yuv420_dc_max_200mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ conn = &priv->connector;
+ KUNIT_ASSERT_EQ(test, conn->display_info.max_tmds_clock, 200 * 1000);
+
+ dank = find_420_only_mode(conn);
+ KUNIT_ASSERT_NOT_NULL(test, dank);
+ KUNIT_EXPECT_EQ(test, dank->hdisplay, 3840);
+ KUNIT_EXPECT_EQ(test, dank->vdisplay, 2160);
+
+ /*
+ * Note: The mode's "clock" here is not accurate to the actual TMDS
+ * clock that HDMI will use for a subsampled mode. Hence, why the mode's
+ * clock is above the .max_tmds_clock of 200MHz.
+ */
+ KUNIT_EXPECT_EQ(test, dank->clock, 297000);
+}
+
+/*
+ * Test that drm_hdmi_connector_mode_valid() will reject modes that require
+ * 4:2:0 chroma subsampling, if the connector does not support 4:2:0.
+ */
+static void
+drm_test_check_mode_valid_reject_yuv420_only_connector(struct kunit *test)
+{
+ struct drm_atomic_helper_connector_hdmi_priv *priv;
+ struct drm_display_mode *dank;
+ struct drm_connector *conn;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(HDMI_COLORSPACE_RGB),
+ 8,
+ &dummy_connector_hdmi_funcs,
+ test_edid_hdmi_1080p_rgb_yuv_4k_yuv420_dc_max_200mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ conn = &priv->connector;
+ KUNIT_ASSERT_EQ(test, conn->display_info.max_tmds_clock, 200 * 1000);
+
+ dank = find_420_only_mode(conn);
+ KUNIT_EXPECT_NULL(test, dank);
+}
+
+/*
+ * Test that drm_hdmi_connector_mode_valid() will accept modes that allow (among
+ * other color formats) 4:2:0 chroma subsampling, even if the connector does not
+ * support 4:2:0, but the mode's clock works for RGB 4:4:4.
+ */
+static void
+drm_test_check_mode_valid_accept_yuv420_also_connector_rgb(struct kunit *test)
+{
+ struct drm_atomic_helper_connector_hdmi_priv *priv;
+ struct drm_display_mode *mode;
+ struct drm_connector *conn;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(HDMI_COLORSPACE_RGB),
+ 8,
+ &dummy_connector_hdmi_funcs,
+ test_edid_hdmi_4k_rgb_yuv420_dc_max_340mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ conn = &priv->connector;
+ KUNIT_ASSERT_EQ(test, conn->display_info.max_tmds_clock, 340 * 1000);
+
+ mode = find_420_also_mode(conn);
+ KUNIT_ASSERT_NOT_NULL(test, mode);
+ KUNIT_EXPECT_EQ(test, mode->hdisplay, 3840);
+ KUNIT_EXPECT_EQ(test, mode->vdisplay, 2160);
+ KUNIT_EXPECT_EQ(test, mode->clock, 297000);
+}
+
static struct kunit_case drm_atomic_helper_connector_hdmi_mode_valid_tests[] = {
KUNIT_CASE(drm_test_check_mode_valid),
KUNIT_CASE(drm_test_check_mode_valid_reject),
KUNIT_CASE(drm_test_check_mode_valid_reject_rate),
KUNIT_CASE(drm_test_check_mode_valid_reject_max_clock),
+ KUNIT_CASE(drm_test_check_mode_valid_yuv420_only_max_clock),
+ KUNIT_CASE(drm_test_check_mode_valid_reject_yuv420_only_connector),
+ KUNIT_CASE(drm_test_check_mode_valid_accept_yuv420_also_connector_rgb),
{ }
};
--
2.52.0
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