Re: [Intel-gfx] [PATCH v3 3/4] drm/i915/hdcp: Fix modeset locking issue in hdcp mst

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 5/15/2023 10:45 AM, Suraj Kandpal wrote:
> Since topology state is being added to drm_atomic_state now all
> drm_modeset_lock required are being taken from core. This raises
> an issue when we try to loop over connector and assign vcpi id to
> our streams as we did not have atomic state to derive acquire_ctx
> from. We fill in stream info if dpmst encoder is found before
> enabling hdcp. intel_hdcp_required_stream will be broken which
> will only set the content type.
>
> --v2
> -move prepare streams to beginning of intel_hdcp_enable to avoid
> checking of mst encoder twice [Ankit]
>
> --v3
> -break intel_required_content_stream to two part and set the stream_id
> at the beginning [Ankit]
>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_hdcp.c | 63 +++++++++++++++--------
>   1 file changed, 42 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index f2d258a72c59..64875c33832c 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -30,7 +30,8 @@
>   #define KEY_LOAD_TRIES	5
>   #define HDCP2_LC_RETRY_CNT			3
>   
> -static int intel_conn_to_vcpi(struct intel_connector *connector)
> +static int intel_conn_to_vcpi(struct drm_atomic_state *state,
> +			      struct intel_connector *connector)
>   {
>   	struct drm_dp_mst_topology_mgr *mgr;
>   	struct drm_dp_mst_atomic_payload *payload;
> @@ -42,7 +43,7 @@ static int intel_conn_to_vcpi(struct intel_connector *connector)
>   		return 0;
>   	mgr = connector->port->mgr;
>   
> -	drm_modeset_lock(&mgr->base.lock, NULL);
> +	drm_modeset_lock(&mgr->base.lock, state->acquire_ctx);
>   	mst_state = to_drm_dp_mst_topology_state(mgr->base.state);
>   	payload = drm_atomic_get_mst_payload_state(mst_state, connector->port);
>   	if (drm_WARN_ON(mgr->dev, !payload))
> @@ -54,7 +55,6 @@ static int intel_conn_to_vcpi(struct intel_connector *connector)
>   		goto out;
>   	}
>   out:
> -	drm_modeset_unlock(&mgr->base.lock);
>   	return vcpi;
>   }
>   
> @@ -71,22 +71,42 @@ static int intel_conn_to_vcpi(struct intel_connector *connector)
>   static int
>   intel_hdcp_required_content_stream(struct intel_digital_port *dig_port)
>   {
> -	struct drm_connector_list_iter conn_iter;
> -	struct intel_digital_port *conn_dig_port;
> -	struct intel_connector *connector;
> -	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
>   	struct hdcp_port_data *data = &dig_port->hdcp_port_data;
>   	bool enforce_type0 = false;
>   	int k;
>   
> -	data->k = 0;
> -
>   	if (dig_port->hdcp_auth_status)
>   		return 0;
>   
>   	if (!dig_port->hdcp_mst_type1_capable)
>   		enforce_type0 = true;
>   
> +	/*
> +	 * Apply common protection level across all streams in DP MST Topology.
> +	 * Use highest supported content type for all streams in DP MST Topology.
> +	 */
> +	for (k = 0; k < data->k; k++)
> +		data->streams[k].stream_type =
> +			enforce_type0 ? DRM_MODE_HDCP_CONTENT_TYPE0 : DRM_MODE_HDCP_CONTENT_TYPE1;
> +
> +	return 0;

I think there is no need for return anything now.

Same with the caller for this function.

> +}
> +
> +static int
> +intel_hdcp_set_content_streams(struct intel_digital_port *dig_port,

Here we are setting stream id and number of streams k, so 'content' in 
the name can be dropped.

It would be good to place this function above the caller.

Otherwise looks good to me.


Regards,

Ankit


> +			       struct intel_atomic_state *state)
> +{
> +	struct drm_connector_list_iter conn_iter;
> +	struct intel_digital_port *conn_dig_port;
> +	struct intel_connector *connector;
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +	struct hdcp_port_data *data = &dig_port->hdcp_port_data;
> +
> +	if (!intel_encoder_is_mst(&dig_port->base))
> +		return 0;
> +
> +	data->k = 0;
> +
>   	drm_connector_list_iter_begin(&i915->drm, &conn_iter);
>   	for_each_intel_connector_iter(connector, &conn_iter) {
>   		if (connector->base.status == connector_status_disconnected)
> @@ -99,7 +119,8 @@ intel_hdcp_required_content_stream(struct intel_digital_port *dig_port)
>   		if (conn_dig_port != dig_port)
>   			continue;
>   
> -		data->streams[data->k].stream_id = intel_conn_to_vcpi(connector);
> +		data->streams[data->k].stream_id =
> +			intel_conn_to_vcpi(&state->base, connector);
>   		data->k++;
>   
>   		/* if there is only one active stream */
> @@ -111,14 +132,6 @@ intel_hdcp_required_content_stream(struct intel_digital_port *dig_port)
>   	if (drm_WARN_ON(&i915->drm, data->k > INTEL_NUM_PIPES(i915) || data->k == 0))
>   		return -EINVAL;
>   
> -	/*
> -	 * Apply common protection level across all streams in DP MST Topology.
> -	 * Use highest supported content type for all streams in DP MST Topology.
> -	 */
> -	for (k = 0; k < data->k; k++)
> -		data->streams[k].stream_type =
> -			enforce_type0 ? DRM_MODE_HDCP_CONTENT_TYPE0 : DRM_MODE_HDCP_CONTENT_TYPE1;
> -
>   	return 0;
>   }
>   
> @@ -2375,9 +2388,17 @@ int intel_hdcp_enable(struct intel_atomic_state *state,
>   	 * is capable of HDCP2.2, it is preferred to use HDCP2.2.
>   	 */
>   	if (intel_hdcp2_capable(connector)) {
> -		ret = _intel_hdcp2_enable(connector);
> -		if (!ret)
> -			check_link_interval = DRM_HDCP2_CHECK_PERIOD_MS;
> +		ret = intel_hdcp_set_content_streams(dig_port, state);
> +		if (!ret) {
> +			ret = _intel_hdcp2_enable(connector);
> +			if (!ret)
> +				check_link_interval =
> +					DRM_HDCP2_CHECK_PERIOD_MS;
> +		} else {
> +			drm_dbg_kms(&dev_priv->drm,
> +				    "Set content streams failed: (%d)\n",
> +				    ret);
> +		}
>   	}
>   
>   	/*