[PATCH v7 0/3 RESEND] drm/bridge_connector: implement OOB HPD handling

[PATCH v7 0/3 RESEND] drm/bridge_connector: implement OOB HPD handling

[Dmitry Baryshkov]

This is a resend, since the previous submission got no responses. The
patches have been reviewed/acked by several maintainers. Can we please
gain some attention and either get it merged or understand what should
be changed / improved. This series is required to delivere HPD events
from altmode driver to the MSM DP driver in the sane way.


Note, numbering for this series starts from v5, since there were several
revisions for this patchset under a different series title ([1]).

USB altmodes code would send OOB notifications to the drm_connector
specified in the device tree. However as the MSM DP driver uses
drm_bridge_connector, there is no way to receive these event directly.
Implement a bridge between oob_hotplug_event and drm_bridge's
hpd_notify.

Merge strategy: since this series touches i915 code, it might make sense
to merge all three patches through drm-intel.

[1] https://patchwork.freedesktop.org/series/103449/

Changes since v6:
- Rebased on top of linux-next. Fixed the freshly added
  new drm_connector_oob_hotplug_event() call.

Changes since v5:
- Fixed checkpatch warning in the first patch (noted by intel-gfx CI).

Changes since v4:
- Picked up the patchset
- Dropped msm-specific patches
- Changed drm_bridge_connector_oob_hotplug_event to call connector's HPD
  callback directly, rather than going through the last bridge's
  hpd_notify
- Added proper fwnode for the drm_bridge_connector

Bjorn Andersson (1):
  drm: Add HPD state to drm_connector_oob_hotplug_event()

Dmitry Baryshkov (2):
  drm/bridge_connector: stop filtering events in
    drm_bridge_connector_hpd_cb()
  drm/bridge_connector: implement oob_hotplug_event

 drivers/gpu/drm/drm_bridge_connector.c        | 36 ++++++++++++++-----
 drivers/gpu/drm/drm_connector.c               |  6 ++--
 .../gpu/drm/i915/display/intel_display_core.h |  3 ++
 drivers/gpu/drm/i915/display/intel_dp.c       | 17 +++++++--
 drivers/usb/typec/altmodes/displayport.c      | 17 ++++-----
 include/drm/drm_connector.h                   |  6 ++--
 6 files changed, 62 insertions(+), 23 deletions(-)

-- 
2.39.2

[PATCH v7 1/3 RESEND] drm: Add HPD state to drm_connector_oob_hotplug_event()

[Dmitry Baryshkov]

From: Bjorn Andersson <bjorn.andersson@linaro.org>

In some implementations, such as the Qualcomm platforms, the display
driver has no way to query the current HPD state and as such it's
impossible to distinguish between disconnect and attention events.

Add a parameter to drm_connector_oob_hotplug_event() to pass the HPD
state.

Also push the test for unchanged state in the displayport altmode driver
into the i915 driver, to allow other drivers to act upon each update.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/drm_connector.c                 |  6 ++++--
 .../gpu/drm/i915/display/intel_display_core.h   |  3 +++
 drivers/gpu/drm/i915/display/intel_dp.c         | 17 ++++++++++++++---
 drivers/usb/typec/altmodes/displayport.c        | 17 +++++++++--------
 include/drm/drm_connector.h                     |  6 ++++--
 5 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 9d4c7b0c5c05..c3725086f413 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -3060,6 +3060,7 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
 /**
  * drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
  * @connector_fwnode: fwnode_handle to report the event on
+ * @status: hot plug detect logical state
  *
  * On some hardware a hotplug event notification may come from outside the display
  * driver / device. An example of this is some USB Type-C setups where the hardware
@@ -3069,7 +3070,8 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
  * This function can be used to report these out-of-band events after obtaining
  * a drm_connector reference through calling drm_connector_find_by_fwnode().
  */
-void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode)
+void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
+				     enum drm_connector_status status)
 {
 	struct drm_connector *connector;
 
@@ -3078,7 +3080,7 @@ void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode)
 		return;
 
 	if (connector->funcs->oob_hotplug_event)
-		connector->funcs->oob_hotplug_event(connector);
+		connector->funcs->oob_hotplug_event(connector, status);
 
 	drm_connector_put(connector);
 }
diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h b/drivers/gpu/drm/i915/display/intel_display_core.h
index 53e5c33e08c3..ccfe27630fb6 100644
--- a/drivers/gpu/drm/i915/display/intel_display_core.h
+++ b/drivers/gpu/drm/i915/display/intel_display_core.h
@@ -175,6 +175,9 @@ struct intel_hotplug {
 	/* Whether or not to count short HPD IRQs in HPD storms */
 	u8 hpd_short_storm_enabled;
 
+	/* Last state reported by oob_hotplug_event for each encoder */
+	unsigned long oob_hotplug_last_state;
+
 	/*
 	 * if we get a HPD irq from DP and a HPD irq from non-DP
 	 * the non-DP HPD could block the workqueue on a mode config
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 0ef7cb8134b6..4f6835a7578e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5723,15 +5723,26 @@ static int intel_dp_connector_atomic_check(struct drm_connector *conn,
 	return intel_modeset_synced_crtcs(state, conn);
 }
 
-static void intel_dp_oob_hotplug_event(struct drm_connector *connector)
+static void intel_dp_oob_hotplug_event(struct drm_connector *connector,
+				       enum drm_connector_status hpd_state)
 {
 	struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
 	struct drm_i915_private *i915 = to_i915(connector->dev);
+	bool hpd_high = hpd_state == connector_status_connected;
+	unsigned int hpd_pin = encoder->hpd_pin;
+	bool need_work = false;
 
 	spin_lock_irq(&i915->irq_lock);
-	i915->display.hotplug.event_bits |= BIT(encoder->hpd_pin);
+	if (hpd_high != test_bit(hpd_pin, &i915->display.hotplug.oob_hotplug_last_state)) {
+		i915->display.hotplug.event_bits |= BIT(hpd_pin);
+
+		__assign_bit(hpd_pin, &i915->display.hotplug.oob_hotplug_last_state, hpd_high);
+		need_work = true;
+	}
 	spin_unlock_irq(&i915->irq_lock);
-	queue_delayed_work(i915->unordered_wq, &i915->display.hotplug.hotplug_work, 0);
+
+	if (need_work)
+		queue_delayed_work(i915->unordered_wq, &i915->display.hotplug.hotplug_work, 0);
 }
 
 static const struct drm_connector_funcs intel_dp_connector_funcs = {
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index f503cb4cd721..c6dd35cec799 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -156,11 +156,11 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
 			}
 		}
 	} else {
-		if (dp->hpd != hpd) {
-			drm_connector_oob_hotplug_event(dp->connector_fwnode);
-			dp->hpd = hpd;
-			sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
-		}
+		drm_connector_oob_hotplug_event(dp->connector_fwnode,
+						hpd ? connector_status_connected :
+						      connector_status_disconnected);
+		dp->hpd = hpd;
+		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
 	}
 
 	return ret;
@@ -176,7 +176,8 @@ static int dp_altmode_configured(struct dp_altmode *dp)
 	 * configuration is complete to signal HPD.
 	 */
 	if (dp->pending_hpd) {
-		drm_connector_oob_hotplug_event(dp->connector_fwnode);
+		drm_connector_oob_hotplug_event(dp->connector_fwnode,
+						connector_status_connected);
 		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
 		dp->pending_hpd = false;
 	}
@@ -621,8 +622,8 @@ void dp_altmode_remove(struct typec_altmode *alt)
 	cancel_work_sync(&dp->work);
 
 	if (dp->connector_fwnode) {
-		if (dp->hpd)
-			drm_connector_oob_hotplug_event(dp->connector_fwnode);
+		drm_connector_oob_hotplug_event(dp->connector_fwnode,
+						connector_status_disconnected);
 
 		fwnode_handle_put(dp->connector_fwnode);
 	}
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 6302caa0bd51..fe88d7fc6b8f 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1336,7 +1336,8 @@ struct drm_connector_funcs {
 	 * This will get called when a hotplug-event for a drm-connector
 	 * has been received from a source outside the display driver / device.
 	 */
-	void (*oob_hotplug_event)(struct drm_connector *connector);
+	void (*oob_hotplug_event)(struct drm_connector *connector,
+				  enum drm_connector_status status);
 
 	/**
 	 * @debugfs_init:
@@ -1980,7 +1981,8 @@ drm_connector_is_unregistered(struct drm_connector *connector)
 		DRM_CONNECTOR_UNREGISTERED;
 }
 
-void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode);
+void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
+				     enum drm_connector_status status);
 const char *drm_get_connector_type_name(unsigned int connector_type);
 const char *drm_get_connector_status_name(enum drm_connector_status status);
 const char *drm_get_subpixel_order_name(enum subpixel_order order);
-- 
2.39.2

[PATCH v7 2/3 RESEND] drm/bridge_connector: stop filtering events in drm_bridge_connector_hpd_cb()

[Dmitry Baryshkov]

In some cases the bridge drivers would like to receive hotplug events
even in the case new status is equal to the old status. In the DP case
this is used to deliver "attention" messages to the DP host. Stop
filtering the events in the drm_bridge_connector_hpd_cb() and let
drivers decide whether they would like to receive the event or not.

Reviewed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/drm_bridge_connector.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
index 31baf1f5ff81..70582491d955 100644
--- a/drivers/gpu/drm/drm_bridge_connector.c
+++ b/drivers/gpu/drm/drm_bridge_connector.c
@@ -113,16 +113,11 @@ static void drm_bridge_connector_hpd_cb(void *cb_data,
 	struct drm_bridge_connector *drm_bridge_connector = cb_data;
 	struct drm_connector *connector = &drm_bridge_connector->base;
 	struct drm_device *dev = connector->dev;
-	enum drm_connector_status old_status;
 
 	mutex_lock(&dev->mode_config.mutex);
-	old_status = connector->status;
 	connector->status = status;
 	mutex_unlock(&dev->mode_config.mutex);
 
-	if (old_status == status)
-		return;
-
 	drm_bridge_connector_hpd_notify(connector, status);
 
 	drm_kms_helper_connector_hotplug_event(connector);
-- 
2.39.2

[PATCH v7 3/3 RESEND] drm/bridge_connector: implement oob_hotplug_event

[Dmitry Baryshkov]

Implement the oob_hotplug_event() callback. Translate it to the HPD
notification sent to the HPD bridge in the chain.

Reviewed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/drm_bridge_connector.c | 31 +++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
index 70582491d955..8239ad43aed5 100644
--- a/drivers/gpu/drm/drm_bridge_connector.c
+++ b/drivers/gpu/drm/drm_bridge_connector.c
@@ -5,6 +5,8 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 
 #include <drm/drm_atomic_state_helper.h>
@@ -107,10 +109,9 @@ static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
 	}
 }
 
-static void drm_bridge_connector_hpd_cb(void *cb_data,
-					enum drm_connector_status status)
+static void drm_bridge_connector_handle_hpd(struct drm_bridge_connector *drm_bridge_connector,
+					    enum drm_connector_status status)
 {
-	struct drm_bridge_connector *drm_bridge_connector = cb_data;
 	struct drm_connector *connector = &drm_bridge_connector->base;
 	struct drm_device *dev = connector->dev;
 
@@ -123,6 +124,21 @@ static void drm_bridge_connector_hpd_cb(void *cb_data,
 	drm_kms_helper_connector_hotplug_event(connector);
 }
 
+static void drm_bridge_connector_hpd_cb(void *cb_data,
+					enum drm_connector_status status)
+{
+	drm_bridge_connector_handle_hpd(cb_data, status);
+}
+
+static void drm_bridge_connector_oob_hotplug_event(struct drm_connector *connector,
+						   enum drm_connector_status status)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+
+	drm_bridge_connector_handle_hpd(bridge_connector, status);
+}
+
 static void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
 {
 	struct drm_bridge_connector *bridge_connector =
@@ -191,6 +207,8 @@ static void drm_bridge_connector_destroy(struct drm_connector *connector)
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 
+	fwnode_handle_put(connector->fwnode);
+
 	kfree(bridge_connector);
 }
 
@@ -216,6 +234,7 @@ static const struct drm_connector_funcs drm_bridge_connector_funcs = {
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 	.debugfs_init = drm_bridge_connector_debugfs_init,
+	.oob_hotplug_event = drm_bridge_connector_oob_hotplug_event,
 };
 
 /* -----------------------------------------------------------------------------
@@ -352,6 +371,12 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 		if (!drm_bridge_get_next_bridge(bridge))
 			connector_type = bridge->type;
 
+#ifdef CONFIG_OF
+		if (!drm_bridge_get_next_bridge(bridge) &&
+		    bridge->of_node)
+			connector->fwnode = fwnode_handle_get(of_fwnode_handle(bridge->of_node));
+#endif
+
 		if (bridge->ddc)
 			ddc = bridge->ddc;
 
-- 
2.39.2