[PATCH 1/5] drm/bridge: allow hpd_notify() to suppress connector hotplug events

[Yongxing Mou]

The bridge connector framework currently invokes all bridge
hpd_notify() callbacks and unconditionally emits a connector hotplug
event afterwards.

However, not every HPD notification requires a userspace hotplug event.

In particular, DP MST bridges may use hpd_notify() to propagate HPD and
IRQ notifications through the bridge chain while the actual hotplug
handling is performed by the DRM DP MST core. Connector creation,
removal and userspace hotplug events are already managed by the MST
topology framework.

Allow hpd_notify() implementations to suppress the bridge connector
hotplug event by introducing a bool *send_hotplug parameter. Drivers
can clear this flag when HPD processing should not result in a
connector hotplug notification.

A NULL pointer indicates that hotplug suppression is not supported by
the caller, such as the connector detect polling path.

Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/lontium-lt9611uxc.c     |  3 ++-
 drivers/gpu/drm/display/drm_bridge_connector.c | 15 +++++++++------
 drivers/gpu/drm/meson/meson_encoder_hdmi.c     |  3 ++-
 drivers/gpu/drm/msm/dp/dp_display.c            |  3 ++-
 drivers/gpu/drm/msm/dp/dp_drm.h                |  3 ++-
 drivers/gpu/drm/omapdrm/dss/hdmi4.c            |  3 ++-
 include/drm/drm_bridge.h                       |  3 ++-
 7 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
index 8cb17bd0e238..42e1cadcd3fb 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
@@ -430,7 +430,8 @@ static const struct drm_edid *lt9611uxc_bridge_edid_read(struct drm_bridge *brid
 static void lt9611uxc_bridge_hpd_notify(struct drm_bridge *bridge,
 					struct drm_connector *connector,
 					enum drm_connector_status status,
-					enum drm_connector_status_extra extra_status)
+					enum drm_connector_status_extra extra_status,
+					bool *send_hotplug)
 {
 	const struct drm_edid *drm_edid;
 
diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 8f7075fd2aa5..5edca47a025f 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -142,7 +142,8 @@ struct drm_bridge_connector {
 
 static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
 					    enum drm_connector_status status,
-					    enum drm_connector_status_extra extra_status)
+					    enum drm_connector_status_extra extra_status,
+					    bool *send_hotplug)
 {
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
@@ -150,13 +151,14 @@ static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
 	/* Notify all bridges in the pipeline of hotplug events. */
 	drm_for_each_bridge_in_chain_scoped(bridge_connector->encoder, bridge) {
 		if (bridge->funcs->hpd_notify)
-			bridge->funcs->hpd_notify(bridge, connector, status, extra_status);
+			bridge->funcs->hpd_notify(bridge, connector, status,
+						  extra_status, send_hotplug);
 	}
 }
 
 static void drm_bridge_connector_handle_hpd(struct drm_bridge_connector *drm_bridge_connector,
-					    enum drm_connector_status status,
-					    enum drm_connector_status_extra extra_status)
+	enum drm_connector_status status,
+	enum drm_connector_status_extra extra_status)
 {
 	struct drm_connector *connector = &drm_bridge_connector->base;
 	struct drm_device *dev = connector->dev;
@@ -165,7 +167,7 @@ static void drm_bridge_connector_handle_hpd(struct drm_bridge_connector *drm_bri
 	connector->status = status;
 	mutex_unlock(&dev->mode_config.mutex);
 
-	drm_bridge_connector_hpd_notify(connector, status, extra_status);
+	drm_bridge_connector_hpd_notify(connector, status, extra_status, NULL);
 
 	drm_kms_helper_connector_hotplug_event(connector);
 }
@@ -227,7 +229,8 @@ drm_bridge_connector_detect(struct drm_connector *connector, bool force)
 		if (hdmi)
 			drm_atomic_helper_connector_hdmi_hotplug(connector, status);
 
-		drm_bridge_connector_hpd_notify(connector, status, DRM_CONNECTOR_NO_EXTRA_STATUS);
+		drm_bridge_connector_hpd_notify(connector, status,
+						DRM_CONNECTOR_NO_EXTRA_STATUS, NULL);
 	} else {
 		switch (connector->connector_type) {
 		case DRM_MODE_CONNECTOR_DPI:
diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
index 4aecf0ffcf75..a67e7b365c5b 100644
--- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
@@ -324,7 +324,8 @@ static int meson_encoder_hdmi_atomic_check(struct drm_bridge *bridge,
 static void meson_encoder_hdmi_hpd_notify(struct drm_bridge *bridge,
 					  struct drm_connector *connector,
 					  enum drm_connector_status status,
-					  enum drm_connector_status_extra extra_status)
+					  enum drm_connector_status_extra extra_status,
+					  bool *send_hotplug)
 {
 	struct meson_encoder_hdmi *encoder_hdmi = bridge_to_meson_encoder_hdmi(bridge);
 
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index fcfee26f0078..6835c68fe510 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1763,7 +1763,8 @@ void msm_dp_bridge_hpd_disable(struct drm_bridge *bridge)
 void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 			      struct drm_connector *connector,
 			      enum drm_connector_status status,
-			      enum drm_connector_status_extra extra_status)
+			      enum drm_connector_status_extra extra_status,
+			      bool *send_hotplug)
 {
 	struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(bridge);
 	struct msm_dp *msm_dp_display = msm_dp_bridge->msm_dp_display;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
index f6b96c27408a..07ddcd055962 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.h
+++ b/drivers/gpu/drm/msm/dp/dp_drm.h
@@ -32,6 +32,7 @@ void msm_dp_bridge_hpd_disable(struct drm_bridge *bridge);
 void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 			      struct drm_connector *connector,
 			      enum drm_connector_status status,
-			      enum drm_connector_status_extra extra_status);
+			      enum drm_connector_status_extra extra_status,
+			      bool *send_hotplug);
 
 #endif /* _DP_DRM_H_ */
diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi4.c b/drivers/gpu/drm/omapdrm/dss/hdmi4.c
index d02d432abde4..ad659cef16f5 100644
--- a/drivers/gpu/drm/omapdrm/dss/hdmi4.c
+++ b/drivers/gpu/drm/omapdrm/dss/hdmi4.c
@@ -430,7 +430,8 @@ static void hdmi4_bridge_disable(struct drm_bridge *bridge,
 static void hdmi4_bridge_hpd_notify(struct drm_bridge *bridge,
 				    struct drm_connector *connector,
 				    enum drm_connector_status status,
-				    enum drm_connector_status_extra extra_status)
+				    enum drm_connector_status_extra extra_status,
+				    bool *send_hotplug)
 {
 	struct omap_hdmi *hdmi = drm_bridge_to_hdmi(bridge);
 
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 9c4c88024cc5..e6de665ce8f6 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -616,7 +616,8 @@ struct drm_bridge_funcs {
 	void (*hpd_notify)(struct drm_bridge *bridge,
 			   struct drm_connector *connector,
 			   enum drm_connector_status status,
-			   enum drm_connector_status_extra extra_status);
+			   enum drm_connector_status_extra extra_status,
+			   bool *send_hotplug);
 
 	/**
 	 * @hpd_enable:

-- 
2.43.0