[PATCH v7 28/30] drm/tests: hdmi_state_helper: Add HDMI 2.0 scrambling tests
Cristian Ciocaltea
cristian.ciocaltea at collabora.com
Mon Jun 1 15:44:28 PDT 2026
Cover the newly introduced HDMI 2.0 source-scrambler plumbing in the
drm_hdmi_state_helper code with the following KUnit tests:
- drm_test_check_scrambler_needed_low_rate verifies that a mode with
TMDS rate <= 340 MHz never sets conn_state->hdmi.scrambler_needed,
even when both endpoints advertise scrambling support.
- drm_test_check_scrambler_needed_high_rate verifies that a mode with
TMDS rate > 340 MHz makes the helper set scrambler_needed.
- drm_test_check_scrambler_needed_high_rate_no_adv verifies that a mode
with TMDS rate > 340 MHz never sets scrambler_needed when source does
not advertise scrambling support, regardless of sink scrambling
advertisement.
To match the behaviour drm_bridge_connector_init() applies to bridges
that implement source-scrambling callbacks, the __connector_hdmi_init()
helper now infers connector->hdmi.scrambling_supported from the presence
of .scrambler_enable and .scrambler_disable in the supplied
drm_connector_hdmi_funcs, mirroring how connector capability should be
wired up in real drivers.
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
---
drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 219 +++++++++++++++++++++
1 file changed, 219 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 e89e1af7a811..98cd42f429cb 100644
--- a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
@@ -20,6 +20,8 @@
#include <drm/display/drm_hdmi_helper.h>
#include <drm/display/drm_hdmi_state_helper.h>
+#include <linux/hdmi.h>
+
#include "../drm_crtc_internal.h"
#include <kunit/test.h>
@@ -140,6 +142,29 @@ static const struct drm_connector_hdmi_funcs reject_100mhz_connector_hdmi_funcs
},
};
+static int accept_scrambler_enable(struct drm_connector *connector)
+{
+ return 0;
+}
+
+static int accept_scrambler_disable(struct drm_connector *connector)
+{
+ return 0;
+}
+
+static const struct drm_connector_hdmi_funcs scrambler_connector_hdmi_funcs = {
+ .scrambler_enable = accept_scrambler_enable,
+ .scrambler_disable = accept_scrambler_disable,
+ .avi = {
+ .clear_infoframe = accept_infoframe_clear_infoframe,
+ .write_infoframe = accept_infoframe_write_infoframe,
+ },
+ .hdmi = {
+ .clear_infoframe = accept_infoframe_clear_infoframe,
+ .write_infoframe = accept_infoframe_write_infoframe,
+ },
+};
+
static int dummy_connector_get_modes(struct drm_connector *connector)
{
struct drm_atomic_helper_connector_hdmi_priv *priv =
@@ -240,6 +265,8 @@ __connector_hdmi_init(struct kunit *test,
conn = &priv->connector;
conn->ycbcr_420_allowed = !!(formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR420));
+ conn->hdmi.scrambler_supported = hdmi_funcs->scrambler_enable &&
+ hdmi_funcs->scrambler_disable;
ret = drmm_connector_hdmi_init(drm, conn,
"Vendor", "Product",
@@ -2198,6 +2225,195 @@ static void drm_test_check_disable_connector(struct kunit *test)
drm_modeset_acquire_fini(&ctx);
}
+/*
+ * Test that a sub-340 MHz TMDS character rate does not set
+ * conn_state->hdmi.scrambler_needed, even when the source
+ * and the sink both support scrambling.
+ */
+static void drm_test_check_scrambler_needed_low_rate(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 *low_rate_mode;
+ struct drm_connector *conn;
+ struct drm_device *drm;
+ struct drm_crtc *crtc;
+ unsigned long long rate;
+ int ret;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444),
+ 8,
+ &scrambler_connector_hdmi_funcs,
+ test_edid_hdmi_4k_rgb_yuv420_dc_max_600mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ drm = &priv->drm;
+ crtc = priv->crtc;
+ conn = &priv->connector;
+ info = &conn->display_info;
+ KUNIT_ASSERT_TRUE(test, conn->hdmi.scrambler_supported);
+ KUNIT_ASSERT_TRUE(test, info->is_hdmi);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.supported);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.scrambling.supported);
+
+ low_rate_mode = drm_kunit_display_mode_from_cea_vic(test, drm, 16);
+ KUNIT_ASSERT_NOT_NULL(test, low_rate_mode);
+
+ rate = drm_hdmi_compute_mode_clock(low_rate_mode, 8, DRM_OUTPUT_COLOR_FORMAT_RGB444);
+ KUNIT_ASSERT_LT(test, rate, HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+
+ drm_modeset_acquire_init(&ctx, 0);
+
+retry_conn_enable:
+ ret = drm_kunit_helper_enable_crtc_connector(test, drm, crtc, conn,
+ low_rate_mode, &ctx);
+ if (ret == -EDEADLK) {
+ ret = drm_modeset_backoff(&ctx);
+ if (!ret)
+ goto retry_conn_enable;
+ }
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ conn_state = conn->state;
+ KUNIT_ASSERT_NOT_NULL(test, conn_state);
+
+ KUNIT_EXPECT_LE(test, conn_state->hdmi.tmds_char_rate,
+ HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+ KUNIT_EXPECT_FALSE(test, conn_state->hdmi.scrambler_needed);
+
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+}
+
+/*
+ * Test that an over-340 MHz TMDS character rate sets
+ * conn_state->hdmi.scrambler_needed when both source
+ * and sink advertise scrambling support.
+ */
+static void drm_test_check_scrambler_needed_high_rate(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;
+ struct drm_connector *conn;
+ struct drm_device *drm;
+ struct drm_crtc *crtc;
+ unsigned long long rate;
+ int ret;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444),
+ 8,
+ &scrambler_connector_hdmi_funcs,
+ test_edid_hdmi_4k_rgb_yuv420_dc_max_600mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ drm = &priv->drm;
+ crtc = priv->crtc;
+ conn = &priv->connector;
+ info = &conn->display_info;
+ KUNIT_ASSERT_TRUE(test, conn->hdmi.scrambler_supported);
+ KUNIT_ASSERT_TRUE(test, info->is_hdmi);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.supported);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.scrambling.supported);
+
+ preferred = find_preferred_mode(conn);
+ KUNIT_ASSERT_NOT_NULL(test, preferred);
+
+ rate = drm_hdmi_compute_mode_clock(preferred, 8, DRM_OUTPUT_COLOR_FORMAT_RGB444);
+ KUNIT_ASSERT_GT(test, rate, HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+
+ drm_modeset_acquire_init(&ctx, 0);
+
+retry_conn_enable:
+ ret = drm_kunit_helper_enable_crtc_connector(test, drm, crtc, conn,
+ preferred, &ctx);
+ if (ret == -EDEADLK) {
+ ret = drm_modeset_backoff(&ctx);
+ if (!ret)
+ goto retry_conn_enable;
+ }
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ conn_state = conn->state;
+ KUNIT_ASSERT_NOT_NULL(test, conn_state);
+
+ KUNIT_EXPECT_GT(test, conn_state->hdmi.tmds_char_rate,
+ HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+ KUNIT_EXPECT_TRUE(test, conn_state->hdmi.scrambler_needed);
+
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+}
+
+/*
+ * Test that an over-340 MHz TMDS character rate does not set
+ * conn_state->hdmi.scrambler_needed when the source does not
+ * advertise scrambling support, even if the sink does.
+ */
+static void drm_test_check_scrambler_needed_high_rate_no_adv(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;
+ struct drm_connector *conn;
+ struct drm_device *drm;
+ struct drm_crtc *crtc;
+ unsigned long long rate;
+ int ret;
+
+ priv = drm_kunit_helper_connector_hdmi_init_with_edid_funcs(test,
+ BIT(DRM_OUTPUT_COLOR_FORMAT_RGB444),
+ 8,
+ &dummy_connector_hdmi_funcs,
+ test_edid_hdmi_4k_rgb_yuv420_dc_max_600mhz);
+ KUNIT_ASSERT_NOT_NULL(test, priv);
+
+ drm = &priv->drm;
+ crtc = priv->crtc;
+ conn = &priv->connector;
+ info = &conn->display_info;
+ KUNIT_ASSERT_FALSE(test, conn->hdmi.scrambler_supported);
+ KUNIT_ASSERT_TRUE(test, info->is_hdmi);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.supported);
+ KUNIT_ASSERT_TRUE(test, info->hdmi.scdc.scrambling.supported);
+
+ preferred = find_preferred_mode(conn);
+ KUNIT_ASSERT_NOT_NULL(test, preferred);
+
+ rate = drm_hdmi_compute_mode_clock(preferred, 8, DRM_OUTPUT_COLOR_FORMAT_RGB444);
+ KUNIT_ASSERT_GT(test, rate, HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+
+ drm_modeset_acquire_init(&ctx, 0);
+
+retry_conn_enable:
+ ret = drm_kunit_helper_enable_crtc_connector(test, drm, crtc, conn,
+ preferred, &ctx);
+ if (ret == -EDEADLK) {
+ ret = drm_modeset_backoff(&ctx);
+ if (!ret)
+ goto retry_conn_enable;
+ }
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ conn_state = conn->state;
+ KUNIT_ASSERT_NOT_NULL(test, conn_state);
+
+ KUNIT_EXPECT_GT(test, conn_state->hdmi.tmds_char_rate,
+ HDMI_1_3_TMDS_CHAR_RATE_MAX_HZ);
+ KUNIT_EXPECT_FALSE(test, conn_state->hdmi.scrambler_needed);
+
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+}
+
static struct kunit_case drm_atomic_helper_connector_hdmi_check_tests[] = {
KUNIT_CASE(drm_test_check_broadcast_rgb_auto_cea_mode),
KUNIT_CASE(drm_test_check_broadcast_rgb_auto_cea_mode_vic_1),
@@ -2227,6 +2443,9 @@ static struct kunit_case drm_atomic_helper_connector_hdmi_check_tests[] = {
KUNIT_CASE(drm_test_check_tmds_char_rate_rgb_8bpc),
KUNIT_CASE(drm_test_check_tmds_char_rate_rgb_10bpc),
KUNIT_CASE(drm_test_check_tmds_char_rate_rgb_12bpc),
+ KUNIT_CASE(drm_test_check_scrambler_needed_low_rate),
+ KUNIT_CASE(drm_test_check_scrambler_needed_high_rate),
+ KUNIT_CASE(drm_test_check_scrambler_needed_high_rate_no_adv),
/*
* TODO: We should have tests to check that a change in the
* format triggers a CRTC mode change just like we do for the
--
2.54.0
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