[PATCH 07/11] drm/i915: Don't fully disable HDCP on a port if multiple pipes are using it

From: Sean Paul <sean@poorly.run>
To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
	ramalingm.c@intel.com
Cc: David Airlie <airlied@linux.ie>,
	Sean Paul <seanpaul@chromium.org>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: [PATCH 07/11] drm/i915: Don't fully disable HDCP on a port if multiple pipes are using it
Date: Tue,  3 Dec 2019 12:36:30 -0500	[thread overview]
Message-ID: <20191203173638.94919-8-sean@poorly.run> (raw)
In-Reply-To: <20191203173638.94919-1-sean@poorly.run>

From: Sean Paul <seanpaul@chromium.org>

This patch is required for HDCP over MST. If a port is being used for
multiple HDCP streams, we don't want to fully disable HDCP on a port if
one of them is disabled. Instead, we just disable the HDCP signalling on
that particular pipe and exit early. The last pipe to disable HDCP will
also bring down HDCP on the port.

In order to achieve this, we need to keep a refcount in intel_digital_port
and protect it using a new hdcp_mutex.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/i915/display/intel_ddi.c      |  3 ++
 .../drm/i915/display/intel_display_types.h    |  5 ++
 drivers/gpu/drm/i915/display/intel_dp.c       |  2 +
 drivers/gpu/drm/i915/display/intel_hdcp.c     | 49 ++++++++++++++++---
 drivers/gpu/drm/i915/display/intel_hdmi.c     |  2 +
 5 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index ca28913a4c9f..a55bc7109045 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4717,6 +4717,9 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	intel_encoder = &intel_dig_port->base;
 	encoder = &intel_encoder->base;
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+	intel_dig_port->num_hdcp_streams = 0;
+
 	drm_encoder_init(&dev_priv->drm, encoder, &intel_ddi_funcs,
 			 DRM_MODE_ENCODER_TMDS, "DDI %c", port_name(port));
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index bbd44772b9b0..489e1d00928b 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1309,6 +1309,11 @@ struct intel_digital_port {
 	enum phy_fia tc_phy_fia;
 	u8 tc_phy_fia_idx;
 
+	/* protects num_hdcp_streams reference count */
+	struct mutex hdcp_mutex;
+	/* the number of pipes using HDCP signalling out of this port */
+	unsigned int num_hdcp_streams;
+
 	void (*write_infoframe)(struct intel_encoder *encoder,
 				const struct intel_crtc_state *crtc_state,
 				unsigned int type,
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index e26fb26b1909..fc5a7dc6ab9b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -7535,6 +7535,8 @@ bool intel_dp_init(struct drm_i915_private *dev_priv,
 	intel_encoder = &intel_dig_port->base;
 	encoder = &intel_encoder->base;
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+
 	if (drm_encoder_init(&dev_priv->drm, &intel_encoder->base,
 			     &intel_dp_enc_funcs, DRM_MODE_ENCODER_TMDS,
 			     "DP %c", port_name(port)))
diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index f34763fa5b42..cd246f501738 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -849,6 +849,7 @@ struct intel_connector *intel_hdcp_to_connector(struct intel_hdcp *hdcp)
 static void intel_hdcp_update_value(struct intel_connector *connector,
 				    u64 value, bool update_property)
 {
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 
 	WARN_ON(!mutex_is_locked(&hdcp->mutex));
@@ -856,6 +857,15 @@ static void intel_hdcp_update_value(struct intel_connector *connector,
 	if (hdcp->value == value)
 		return;
 
+	WARN_ON(!mutex_is_locked(&intel_dig_port->hdcp_mutex));
+
+	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
+		if (!WARN_ON(intel_dig_port->num_hdcp_streams == 0))
+			intel_dig_port->num_hdcp_streams--;
+	} else if (value == DRM_MODE_CONTENT_PROTECTION_ENABLED) {
+		intel_dig_port->num_hdcp_streams++;
+	}
+
 	hdcp->value = value;
 	if (update_property)
 		schedule_work(&hdcp->prop_work);
@@ -872,6 +882,8 @@ static int intel_hdcp_check_link(struct intel_connector *connector)
 	int ret = 0;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
+
 	cpu_transcoder = hdcp->cpu_transcoder;
 
 	/* Check_link valid only when HDCP1.4 is enabled */
@@ -923,6 +935,7 @@ static int intel_hdcp_check_link(struct intel_connector *connector)
 	}
 
 out:
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	return ret;
 }
@@ -1994,6 +2007,7 @@ int intel_hdcp_init(struct intel_connector *connector,
 
 int intel_hdcp_enable(struct intel_connector *connector, u8 content_type)
 {
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	unsigned long check_link_interval = DRM_HDCP_CHECK_PERIOD_MS;
 	int ret = -EINVAL;
@@ -2002,6 +2016,7 @@ int intel_hdcp_enable(struct intel_connector *connector, u8 content_type)
 		return -ENOENT;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
 	WARN_ON(hdcp->value == DRM_MODE_CONTENT_PROTECTION_ENABLED);
 	hdcp->content_type = content_type;
 
@@ -2031,12 +2046,14 @@ int intel_hdcp_enable(struct intel_connector *connector, u8 content_type)
 					true);
 	}
 
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	return ret;
 }
 
 int intel_hdcp_disable(struct intel_connector *connector)
 {
+	struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	int ret = 0;
 
@@ -2044,17 +2061,33 @@ int intel_hdcp_disable(struct intel_connector *connector)
 		return -ENOENT;
 
 	mutex_lock(&hdcp->mutex);
+	mutex_lock(&intel_dig_port->hdcp_mutex);
 
-	if (hdcp->value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
-		intel_hdcp_update_value(connector,
-					DRM_MODE_CONTENT_PROTECTION_UNDESIRED,
-					false);
-		if (hdcp->hdcp2_encrypted)
-			ret = _intel_hdcp2_disable(connector);
-		else if (hdcp->hdcp_encrypted)
-			ret = _intel_hdcp_disable(connector);
+	if (hdcp->value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
+		goto out;
+
+	intel_hdcp_update_value(connector,
+				DRM_MODE_CONTENT_PROTECTION_UNDESIRED, false);
+
+	/*
+	 * If there are other connectors on this port using HDCP, don't disable
+	 * it. Instead, toggle the HDCP signalling off on that particular
+	 * connector/pipe and exit.
+	 */
+	if (intel_dig_port->num_hdcp_streams > 0) {
+		ret = hdcp->shim->toggle_signalling(connector, false);
+		if (ret)
+			DRM_DEBUG_KMS("Failed to disable HDCP signalling\n");
+		goto out;
 	}
 
+	if (hdcp->hdcp2_encrypted)
+		ret = _intel_hdcp2_disable(connector);
+	else if (hdcp->hdcp_encrypted)
+		ret = _intel_hdcp_disable(connector);
+
+out:
+	mutex_unlock(&intel_dig_port->hdcp_mutex);
 	mutex_unlock(&hdcp->mutex);
 	cancel_delayed_work_sync(&hdcp->check_work);
 	return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 6a1e711c4f7a..c230d37c4276 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -3243,6 +3243,8 @@ void intel_hdmi_init(struct drm_i915_private *dev_priv,
 
 	intel_encoder = &intel_dig_port->base;
 
+	mutex_init(&intel_dig_port->hdcp_mutex);
+
 	drm_encoder_init(&dev_priv->drm, &intel_encoder->base,
 			 &intel_hdmi_enc_funcs, DRM_MODE_ENCODER_TMDS,
 			 "HDMI %c", port_name(port));
-- 
Sean Paul, Software Engineer, Google / Chromium OS

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