Re: [PATCH v10 22/69] drm/display: hdmi-state-helper: Sync SCDC state on hotplug

[Maxime Ripard]

On Fri, Jul 31, 2026 at 07:19:29PM +0300, Cristian Ciocaltea wrote:
> drm_atomic_helper_connector_hdmi_hotplug() does not currently
> synchronize SCDC status on hotplug events, leaving the scrambler state
> potentially inconsistent after (re)connect.
> 
> Hook drm_connector_hdmi_sync_scdc() into both the connect and disconnect
> paths, replacing the existing TODOs around missing scrambler handling.
> 
> Tested-by: Maud Spierings <maud_spierings@xxxxxxxxxxx>
> Tested-by: Diederik de Haas <diederik@xxxxxxxxxxxxxx>  # NanoPC-T6 LTS, Rock 5B
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/display/drm_hdmi_state_helper.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> index 4a93c279c9a7..3377ea936120 100644
> --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> @@ -1205,13 +1205,16 @@ drm_atomic_helper_connector_hdmi_update(struct drm_connector *connector,
>  					enum drm_connector_status status)
>  {
>  	const struct drm_edid *drm_edid;
> +	int ret = 0;
>  
>  	if (status == connector_status_disconnected) {
> -		// TODO: also handle scramber, HDMI sink disconnected.
> -		drm_connector_hdmi_audio_plugged_notify(connector, false);
> -		drm_edid_connector_update(connector, NULL);
> -		drm_connector_cec_phys_addr_invalidate(connector);
> -		return 0;
> +		ret = drm_connector_hdmi_sync_scdc(connector, false, ctx);
> +		if (ret != -EDEADLK) {
> +			drm_connector_hdmi_audio_plugged_notify(connector, false);
> +			drm_edid_connector_update(connector, NULL);
> +			drm_connector_cec_phys_addr_invalidate(connector);
> +		}

If there's a deadlock, shouldn't we restart the whole sequence there?
Ie, we should return ret all the time anyway? And if we do that, we
should return ret for drm_edid_connector_update() too.

Either way, a comment on why we're doing it this way would be nice.

Maxime

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