On Tue, Jun 02, 2026 at 01:44:02AM +0300, Cristian Ciocaltea wrote:
> Add the connector-level infrastructure to support HDMI 2.0 scrambling:
>
> - A scrambler_supported flag to indicate whether the source supports the
> scrambling capability, in which case the newly introduced
> .scrambler_{enable|disable}() callbacks in drm_connector_hdmi_funcs
> are mandatory
> - A scrambler_needed flag to be managed by the hdmi state helpers based
> on the negotiated TMDS character rate and the source/sink scrambling
> capabilities
> - A scrambler_enabled flag to track whether scrambling is currently
> active
> - A delayed work item (scdc_work) with an associated callback (scdc_cb)
> to monitor sink-side scrambling status and retry the setup if the sink
> resets it
>
> These are intended to be used by SCDC scrambling helpers to coordinate
> scrambling setup and teardown between the source driver and the DRM
> core.
>
> Signed-off-by: Cristian Ciocaltea <[email protected]>
> ---
> drivers/gpu/drm/drm_connector.c | 18 +++++++++
> include/drm/drm_connector.h | 81
> +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 99 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index a5d13b92b665..526dc2931b8a 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -220,6 +220,19 @@ void drm_connector_free_work_fn(struct work_struct *work)
> }
> }
>
> +static void drm_connector_hdmi_scdc_work(struct work_struct *work)
> +{
> + struct drm_connector *connector;
> + struct drm_connector_hdmi *hdmi;
> +
> + hdmi = container_of(to_delayed_work(work), struct drm_connector_hdmi,
> + scdc_work);
> + connector = container_of(hdmi, struct drm_connector, hdmi);
> +
> + if (hdmi->scdc_cb)
> + hdmi->scdc_cb(connector);
> +}
> +
> static int drm_connector_init_only(struct drm_device *dev,
> struct drm_connector *connector,
> const struct drm_connector_funcs *funcs,
> @@ -285,6 +298,7 @@ static int drm_connector_init_only(struct drm_device *dev,
> mutex_init(&connector->edid_override_mutex);
> mutex_init(&connector->hdmi.infoframes.lock);
> mutex_init(&connector->hdmi_audio.lock);
> + INIT_DELAYED_WORK(&connector->hdmi.scdc_work,
> drm_connector_hdmi_scdc_work);
> connector->edid_blob_ptr = NULL;
> connector->epoch_counter = 0;
> connector->tile_blob_ptr = NULL;
> @@ -606,6 +620,10 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
> !hdmi_funcs->hdmi.write_infoframe)
> return -EINVAL;
>
> + if (connector->hdmi.scrambler_supported &&
> + (!hdmi_funcs->scrambler_enable || !hdmi_funcs->scrambler_disable))
> + return -EINVAL;
> +
> ret = drmm_connector_init(dev, connector, funcs, connector_type, ddc);
> if (ret)
> return ret;
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 529755c2e862..f1c5c15a6cce 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -28,6 +28,7 @@
> #include <linux/ctype.h>
> #include <linux/hdmi.h>
> #include <linux/notifier.h>
> +#include <linux/workqueue.h>
> #include <drm/drm_mode_object.h>
> #include <drm/drm_util.h>
> #include <drm/drm_property.h>
> @@ -1057,6 +1058,19 @@ struct drm_connector_hdmi_state {
> * @tmds_char_rate: TMDS Character Rate, in Hz.
> */
> unsigned long long tmds_char_rate;
> +
> + /**
> + * @scrambler_needed: Whether HDMI 2.0 SCDC scrambling is required
> + * for the negotiated mode/bpc/format.
> + *
> + * Computed by drm_atomic_helper_connector_hdmi_check() from
> + * @tmds_char_rate and the source/sink scrambling capabilities.
> + *
> + * Per HDMI 2.0, scrambling is mandatory above 340 MHz TMDS
> + * character rate. Optional scrambling at lower rates is
> + * deliberately not requested by the helper.
> + */
> + bool scrambler_needed;
> };
>
> /**
> @@ -1358,6 +1372,36 @@ struct drm_connector_hdmi_funcs {
> */
> const struct drm_edid *(*read_edid)(struct drm_connector *connector);
>
> + /**
> + * @scrambler_enable:
> + *
> + * This callback is invoked through @drm_scdc_start_scrambling during
> + * a commit to setup SCDC scrambling and high TMDS clock ratio on
> + * source side.
> + *
> + * The @scrambler_enable callback is mandatory if HDMI 2.0 is to be
> + * supported.
> + *
> + * Returns:
> + * 0 on success, a negative error code otherwise
> + */
> + int (*scrambler_enable)(struct drm_connector *connector);
> +
> + /**
> + * @scrambler_disable:
> + *
> + * This callback is invoked through @drm_scdc_stop_scrambling during
> + * a commit to disable SCDC scrambling and high TMDS clock ratio on
> + * source side.
> + *
> + * The @scrambler_disable callback is mandatory if HDMI 2.0 is to be
> + * supported.
> + *
> + * Returns:
> + * 0 on success, a negative error code otherwise
> + */
> + int (*scrambler_disable)(struct drm_connector *connector);
> +
> /**
> * @avi:
> *
> @@ -1960,6 +2004,43 @@ struct drm_connector_hdmi {
> */
> unsigned long supported_formats;
>
> + /**
> + * @scrambler_supported: Indicates whether the HDMI controller
> + * (source) supports HDMI 2.0 SCDC scrambling.
> + *
> + * When true, @drm_connector_hdmi_funcs.scrambler_enable and
> + * @drm_connector_hdmi_funcs.scrambler_disable are mandatory.
> + * This is enforced by drmm_connector_hdmi_init().
> + *
> + * For HDMI bridge based drivers using drm_bridge_connector_init(),
> + * this is propagated automatically from bridges that set the
> + * DRM_BRIDGE_OP_HDMI_SCRAMBLER flag in their &drm_bridge->ops.
> + * Other drivers must set this field on @connector->hdmi before calling
> + * drmm_connector_hdmi_init().
> + */
> + bool scrambler_supported;
> +
> + /**
> + * @scrambler_enabled: Tracks whether HDMI 2.0 scrambler is currently
> enabled.
> + */
> + bool scrambler_enabled;This is already in the state. Why do you need to copy it over here, and if you do, you'll need a lock. Maxime
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