From bc4dcf6f93778b182ad90233d3049acd9227136c Mon Sep 17 00:00:00 2001 From: Cristian Ciocaltea Date: Tue, 1 Sep 2026 21:50:35 +0300 Subject: [PATCH] drm/display: hdmi: Advertise SCDC source version when scrambling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The HDMI 2.0 spec advises that compliant Source devices report their SCDC version in the Source Version register. Do so when enabling scrambling by calling drm_scdc_set_source_version(). Failures are non-fatal: SCDC version negotiation is purely informational and does not gate scrambling or any high-bitrate functionality, so a flaky DDC bus should not block scrambling setup. Acked-by: Maxime Ripard Tested-by: Maud Spierings Tested-by: Diederik de Haas # NanoPC-T6 LTS, Rock 5B Tested-by: Igor Paunovic # RK3588 Orange Pi 5 Plus, dual HDMI Tested-by: Robin Räber Link: https://patch.msgid.link/20260901-dw-hdmi-qp-scramb-v11-11-bc12954a0688@collabora.com Signed-off-by: Cristian Ciocaltea --- drivers/gpu/drm/display/drm_hdmi_helper.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/display/drm_hdmi_helper.c b/drivers/gpu/drm/display/drm_hdmi_helper.c index bf1c7963b984..f85cce3d6254 100644 --- a/drivers/gpu/drm/display/drm_hdmi_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_helper.c @@ -16,6 +16,7 @@ #include #include +#define DRM_HDMI_SCDC_SOURCE_VERSION 1 #define DRM_HDMI_SCDC_POLL_DELAY_MS 1000 static inline bool is_eotf_supported(u8 output_eotf, u8 sink_eotf) @@ -556,6 +557,12 @@ int drm_connector_hdmi_enable_scrambling(struct drm_connector *connector, if (!connector->ddc) return -EINVAL; + /* + * Advertise our SCDC source version. This is purely informational and + * does not gate scrambling, so failures are non-fatal. + */ + drm_scdc_set_source_version(connector, DRM_HDMI_SCDC_SOURCE_VERSION); + drm_dbg_kms(dev, "Enabling scrambling\n"); if (!hdmi->scdc_work_initialized) {