[PATCH v4 0/9] drm/msm/dp: Drop the HPD state machine

[PATCH v4 0/9] drm/msm/dp: Drop the HPD state machine

[Dmitry Baryshkov]

Currently, all HPD interrupt handling must go through the HPD state
machine.

This has caused many issues where the DRM framework assumes that DP is
in one state while the state machine is stuck in another state.

As discussed here [1], this series:

- Removes the state machine
- Moves link training to atomic_enable()
- Changes the detect() behavior to return true if a display is physically
  plugged in (as opposed to if the DP link is ready).
- Remove event queue and move internal HPD handling to hpd_notify()

Note: eDP is mostly untested. This will be sorted out before the next
iteration, but it will not affect the series in a major way.

Note 2: there is an issue with the DP connectors using GPIO for HPD
(rather than using the nativate DP HPD pin), the DP will not detect a
display if it is plugged in before the board is booted. This is not an
issue of this series and it will be handled by a separate series to be
posted today or tomorrow.

[1] https://patchwork.freedesktop.org/patch/656312/?series=142010&rev=2#comment_1201738

---
Changes in v4:
- Fixed PM runtime handling
- Fixed several cases where the HPD machine would loose its state
- Fixed the case where detection was ignoring the plugging in display.
- Link to v3: https://lore.kernel.org/r/20260115-hpd-refactor-v3-0-08e2f3bcd2e0@oss.qualcomm.com

Changes in v3:
- Take over the series (thanks, Jessica, for the previous work!)
- Major rework of the series, squashed the set of patches touching the
  HPD states and handling, it is easier to do it this way rather than
  pulling the strings one by one.
- Link to v2: https://lore.kernel.org/r/20250808-hpd-refactor-v2-0-7f4e1e741aa3@oss.qualcomm.com

Changes in v2:
- Dropped event queue (Dmitry)
- Moved internal HPD handling to use hpd_notify() (Dmitry)
- Reworked bridge detect() to read DPCP and sink count (Dmitry)
- Moved setting of link_trained to plug/unplugged handling
- Dropped msm_dp::connected (Dmitry)
- Squashed all hpd state related patches (Dmitry)
- Link to v1: https://lore.kernel.org/r/20250711-hpd-refactor-v1-0-33cbac823f34@oss.qualcomm.com

---
Dmitry Baryshkov (2):
      drm/msm/dp: drop event data
      drm/msm/dp: turn link_ready into plugged

Jessica Zhang (7):
      drm/msm/dp: fix HPD state status bit shift value
      drm/msm/dp: Fix the ISR_* enum values
      drm/msm/dp: Read DPCD and sink count in bridge detect()
      drm/msm/dp: Move link training to atomic_enable()
      drm/msm/dp: Drop EV_USER_NOTIFICATION
      drm/msm/dp: rework HPD handling
      drm/msm/dp: Add sink_count to debug logs

 drivers/gpu/drm/msm/dp/dp_ctrl.c    |  22 --
 drivers/gpu/drm/msm/dp/dp_ctrl.h    |   1 -
 drivers/gpu/drm/msm/dp/dp_display.c | 712 ++++++++++++------------------------
 drivers/gpu/drm/msm/dp/dp_display.h |   3 +-
 drivers/gpu/drm/msm/dp/dp_drm.c     |  63 +---
 drivers/gpu/drm/msm/dp/dp_drm.h     |   2 +
 drivers/gpu/drm/msm/dp/dp_reg.h     |   4 +-
 7 files changed, 236 insertions(+), 571 deletions(-)
---
base-commit: b775e489bec70895b7ef6b66927886bbac79598f
change-id: 20250523-hpd-refactor-74e25b55620a

Best regards,
-- 
With best wishes
Dmitry

[PATCH v4 1/9] drm/msm/dp: fix HPD state status bit shift value

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

The HPD state status is the 3 most significant bits, not 4 bits of the
HPD_INT_STATUS register.

Fix the bit shift macro so that the correct bits are returned in
msm_dp_aux_is_link_connected().

Fixes: 19e52bcb27c2 ("drm/msm/dp: return correct connection status after suspend")
Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_reg.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_reg.h b/drivers/gpu/drm/msm/dp/dp_reg.h
index 7c44d4e2cf13..3689642b7fc0 100644
--- a/drivers/gpu/drm/msm/dp/dp_reg.h
+++ b/drivers/gpu/drm/msm/dp/dp_reg.h
@@ -68,8 +68,8 @@
 #define DP_DP_IRQ_HPD_INT_ACK			(0x00000002)
 #define DP_DP_HPD_REPLUG_INT_ACK		(0x00000004)
 #define DP_DP_HPD_UNPLUG_INT_ACK		(0x00000008)
-#define DP_DP_HPD_STATE_STATUS_BITS_MASK	(0x0000000F)
-#define DP_DP_HPD_STATE_STATUS_BITS_SHIFT	(0x1C)
+#define DP_DP_HPD_STATE_STATUS_BITS_MASK	(0x00000007)
+#define DP_DP_HPD_STATE_STATUS_BITS_SHIFT	(0x1D)
 
 #define REG_DP_DP_HPD_INT_MASK			(0x0000000C)
 #define DP_DP_HPD_PLUG_INT_MASK			(0x00000001)

-- 
2.47.3

[PATCH v4 2/9] drm/msm/dp: Fix the ISR_* enum values

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

The ISR_HPD_* enum should represent values that can be read from the
REG_DP_DP_HPD_INT_STATUS register. Swap ISR_HPD_IO_GLITCH_COUNT and
ISR_HPD_REPLUG_COUNT to map them correctly to register values.

While we are at it, correct the spelling for ISR_HPD_REPLUG_COUNT.

Fixes: 8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 476848bf8cd1..5997cd28ba11 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -38,9 +38,9 @@ enum {
 	ISR_DISCONNECTED,
 	ISR_CONNECT_PENDING,
 	ISR_CONNECTED,
-	ISR_HPD_REPLUG_COUNT,
+	ISR_HPD_IO_GLITCH_COUNT,
 	ISR_IRQ_HPD_PULSE_COUNT,
-	ISR_HPD_LO_GLITH_COUNT,
+	ISR_HPD_REPLUG_COUNT,
 };
 
 /* event thread connection state */

-- 
2.47.3

[PATCH v4 3/9] drm/msm/dp: Read DPCD and sink count in bridge detect()

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

Instead of relying on the link_ready flag to specify if DP is connected,
read the DPCD bits and get the sink count to accurately detect if DP is
connected.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 60 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/dp/dp_drm.c     | 20 -------------
 drivers/gpu/drm/msm/dp/dp_drm.h     |  2 ++
 3 files changed, 62 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 5997cd28ba11..a05144de3b93 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1151,6 +1151,66 @@ static int msm_dp_hpd_event_thread_start(struct msm_dp_display_private *msm_dp_p
 	return 0;
 }
 
+/**
+ * msm_dp_bridge_detect - callback to determine if connector is connected
+ * @bridge: Pointer to drm bridge structure
+ * @connector: Pointer to drm connector structure
+ * Returns: Bridge's 'is connected' status
+ */
+enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
+					       struct drm_connector *connector)
+{
+	struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(bridge);
+	struct msm_dp *dp = msm_dp_bridge->msm_dp_display;
+	struct msm_dp_display_private *priv;
+	int ret = 0;
+	int status = connector_status_disconnected;
+	u8 dpcd[DP_RECEIVER_CAP_SIZE];
+	struct drm_dp_desc desc;
+
+	dp = to_dp_bridge(bridge)->msm_dp_display;
+
+	priv = container_of(dp, struct msm_dp_display_private, msm_dp_display);
+
+	if (!dp->link_ready)
+		return status;
+
+	msm_dp_aux_enable_xfers(priv->aux, true);
+
+	ret = pm_runtime_resume_and_get(&dp->pdev->dev);
+	if (ret) {
+		DRM_ERROR("failed to pm_runtime_resume\n");
+		msm_dp_aux_enable_xfers(priv->aux, false);
+		return status;
+	}
+
+	ret = msm_dp_aux_is_link_connected(priv->aux);
+	if (dp->internal_hpd && !ret)
+		goto end;
+
+	ret = drm_dp_read_dpcd_caps(priv->aux, dpcd);
+	if (ret)
+		goto end;
+
+	ret = drm_dp_read_desc(priv->aux, &desc, drm_dp_is_branch(dpcd));
+	if (ret)
+		goto end;
+
+	status = connector_status_connected;
+	if (drm_dp_read_sink_count_cap(connector, dpcd, &desc)) {
+		int sink_count = drm_dp_read_sink_count(priv->aux);
+
+		drm_dbg_dp(dp->drm_dev, "sink_count = %d\n", sink_count);
+
+		if (sink_count <= 0)
+			status = connector_status_disconnected;
+	}
+
+end:
+	pm_runtime_put_sync(&dp->pdev->dev);
+	return status;
+}
+
 static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id)
 {
 	struct msm_dp_display_private *dp = dev_id;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index fd6443d2b6ce..e4622c85fb66 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -15,26 +15,6 @@
 #include "dp_audio.h"
 #include "dp_drm.h"
 
-/**
- * msm_dp_bridge_detect - callback to determine if connector is connected
- * @bridge: Pointer to drm bridge structure
- * @connector: Pointer to drm connector structure
- * Returns: Bridge's 'is connected' status
- */
-static enum drm_connector_status
-msm_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
-{
-	struct msm_dp *dp;
-
-	dp = to_dp_bridge(bridge)->msm_dp_display;
-
-	drm_dbg_dp(dp->drm_dev, "link_ready = %s\n",
-		str_true_false(dp->link_ready));
-
-	return (dp->link_ready) ? connector_status_connected :
-					connector_status_disconnected;
-}
-
 static int msm_dp_bridge_atomic_check(struct drm_bridge *bridge,
 			    struct drm_bridge_state *bridge_state,
 			    struct drm_crtc_state *crtc_state,
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.h b/drivers/gpu/drm/msm/dp/dp_drm.h
index 9eb3431dd93a..6c0426803d78 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.h
+++ b/drivers/gpu/drm/msm/dp/dp_drm.h
@@ -25,6 +25,8 @@ int msm_dp_bridge_init(struct msm_dp *msm_dp_display, struct drm_device *dev,
 		   struct drm_encoder *encoder,
 		   bool yuv_supported);
 
+enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
+					       struct drm_connector *connector);
 void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 				 struct drm_atomic_state *state);
 void msm_dp_bridge_atomic_disable(struct drm_bridge *drm_bridge,

-- 
2.47.3

[PATCH v4 4/9] drm/msm/dp: Move link training to atomic_enable()

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

Currently, the DP link training is being done during HPD. Move
link training to atomic_enable() in accordance with the atomic_enable()
documentation.

Link disabling is already done in atomic_post_disable() (as part of the
dp_ctrl_off_link_stream() helper).

Finally, call the plug/unplug handlers directly in hpd_notify() instead
of queueing them in the event thread so that they aren't preempted by
other events.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index a05144de3b93..e7b1ed5491c4 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -436,11 +436,6 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 	msm_dp_link_psm_config(dp->link, &dp->panel->link_info, false);
 
 	msm_dp_link_reset_phy_params_vx_px(dp->link);
-	rc = msm_dp_ctrl_on_link(dp->ctrl);
-	if (rc) {
-		DRM_ERROR("failed to complete DP link training\n");
-		goto end;
-	}
 
 	msm_dp_add_event(dp, EV_USER_NOTIFICATION, true, 0);
 
@@ -1695,6 +1690,11 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		force_link_train = true;
 	}
 
+	rc = msm_dp_ctrl_on_link(msm_dp_display->ctrl);
+	if (rc)
+		DRM_ERROR("Failed link training (rc=%d)\n", rc);
+	// TODO: schedule drm_connector_set_link_status_property()
+
 	msm_dp_display_enable(msm_dp_display, force_link_train);
 
 	rc = msm_dp_display_post_enable(dp);

-- 
2.47.3

[PATCH v4 5/9] drm/msm/dp: Drop EV_USER_NOTIFICATION

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

Currently, we queue an event for signalling HPD connect/disconnect. This
can mean a delay in plug/unplug handling and notifying DRM core when a
hotplug happens.

Drop EV_USER_NOTIFICATION and signal the IRQ event as part of hotplug
handling.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 28 ++++++++--------------------
 drivers/gpu/drm/msm/dp/dp_display.h |  1 +
 drivers/gpu/drm/msm/dp/dp_drm.c     |  2 ++
 3 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index e7b1ed5491c4..05c292e27126 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -58,7 +58,6 @@ enum {
 	EV_HPD_PLUG_INT,
 	EV_IRQ_HPD_INT,
 	EV_HPD_UNPLUG_INT,
-	EV_USER_NOTIFICATION,
 };
 
 #define EVENT_TIMEOUT	(HZ/10)	/* 100ms */
@@ -343,17 +342,6 @@ static const struct component_ops msm_dp_display_comp_ops = {
 	.unbind = msm_dp_display_unbind,
 };
 
-static void msm_dp_display_send_hpd_event(struct msm_dp *msm_dp_display)
-{
-	struct msm_dp_display_private *dp;
-	struct drm_connector *connector;
-
-	dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
-
-	connector = dp->msm_dp_display.connector;
-	drm_helper_hpd_irq_event(connector->dev);
-}
-
 static int msm_dp_display_send_hpd_notification(struct msm_dp_display_private *dp,
 					    bool hpd)
 {
@@ -377,7 +365,11 @@ static int msm_dp_display_send_hpd_notification(struct msm_dp_display_private *d
 
 	drm_dbg_dp(dp->drm_dev, "type=%d hpd=%d\n",
 			dp->msm_dp_display.connector_type, hpd);
-	msm_dp_display_send_hpd_event(&dp->msm_dp_display);
+
+	drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
+			      hpd ?
+			      connector_status_connected :
+			      connector_status_disconnected);
 
 	return 0;
 }
@@ -437,7 +429,7 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 
 	msm_dp_link_reset_phy_params_vx_px(dp->link);
 
-	msm_dp_add_event(dp, EV_USER_NOTIFICATION, true, 0);
+	msm_dp_display_send_hpd_notification(dp, true);
 
 end:
 	return rc;
@@ -506,7 +498,7 @@ static int msm_dp_display_notify_disconnect(struct device *dev)
 {
 	struct msm_dp_display_private *dp = dev_get_dp_display_private(dev);
 
-	msm_dp_add_event(dp, EV_USER_NOTIFICATION, false, 0);
+	msm_dp_display_send_hpd_notification(dp, false);
 
 	return 0;
 }
@@ -527,7 +519,7 @@ static int msm_dp_display_handle_port_status_changed(struct msm_dp_display_priva
 		drm_dbg_dp(dp->drm_dev, "sink count is zero, nothing to do\n");
 		if (dp->hpd_state != ST_DISCONNECTED) {
 			dp->hpd_state = ST_DISCONNECT_PENDING;
-			msm_dp_add_event(dp, EV_USER_NOTIFICATION, false, 0);
+			msm_dp_display_send_hpd_notification(dp, false);
 		}
 	} else {
 		if (dp->hpd_state == ST_DISCONNECTED) {
@@ -1121,10 +1113,6 @@ static int hpd_event_thread(void *data)
 		case EV_IRQ_HPD_INT:
 			msm_dp_irq_hpd_handle(msm_dp_priv, todo->data);
 			break;
-		case EV_USER_NOTIFICATION:
-			msm_dp_display_send_hpd_notification(msm_dp_priv,
-						todo->data);
-			break;
 		default:
 			break;
 		}
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index cc6e2cab36e9..60094061c102 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -16,6 +16,7 @@ struct msm_dp {
 	struct platform_device *pdev;
 	struct drm_connector *connector;
 	struct drm_bridge *next_bridge;
+	struct drm_bridge *bridge;
 	bool link_ready;
 	bool audio_enabled;
 	bool power_on;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index e4622c85fb66..f935093c4df4 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -340,6 +340,8 @@ int msm_dp_bridge_init(struct msm_dp *msm_dp_display, struct drm_device *dev,
 		}
 	}
 
+	msm_dp_display->bridge = bridge;
+
 	return 0;
 }
 

-- 
2.47.3

[PATCH v4 6/9] drm/msm/dp: drop event data

[Dmitry Baryshkov]

With EV_USER_NOTIFICATION gone event's data is no longer useful. Drop
it, removing also the argument from event handlers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 39 +++++++++++++++++--------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 05c292e27126..bc4078c229cb 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -69,7 +69,6 @@ enum {
 
 struct msm_dp_event {
 	u32 event_id;
-	u32 data;
 	u32 delay;
 };
 
@@ -218,7 +217,7 @@ static struct msm_dp_display_private *dev_get_dp_display_private(struct device *
 }
 
 static int msm_dp_add_event(struct msm_dp_display_private *msm_dp_priv, u32 event,
-						u32 data, u32 delay)
+			    u32 delay)
 {
 	unsigned long flag;
 	struct msm_dp_event *todo;
@@ -236,7 +235,6 @@ static int msm_dp_add_event(struct msm_dp_display_private *msm_dp_priv, u32 even
 	todo = &msm_dp_priv->event_list[msm_dp_priv->event_pndx++];
 	msm_dp_priv->event_pndx %= DP_EVENT_Q_MAX;
 	todo->event_id = event;
-	todo->data = data;
 	todo->delay = delay;
 	wake_up(&msm_dp_priv->event_q);
 	spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
@@ -576,7 +574,7 @@ static int msm_dp_display_usbpd_attention_cb(struct device *dev)
 	return rc;
 }
 
-static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp, u32 data)
+static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 {
 	u32 state;
 	int ret;
@@ -602,7 +600,7 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp, u32 data)
 
 	if (state == ST_DISCONNECT_PENDING) {
 		/* wait until ST_DISCONNECTED */
-		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 1); /* delay = 1 */
+		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 1);
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
@@ -644,7 +642,7 @@ static void msm_dp_display_handle_plugged_change(struct msm_dp *msm_dp_display,
 							plugged);
 }
 
-static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp, u32 data)
+static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 {
 	u32 state;
 	struct platform_device *pdev = dp->msm_dp_display.pdev;
@@ -706,7 +704,7 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp, u32 data)
 	return 0;
 }
 
-static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp, u32 data)
+static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 {
 	u32 state;
 
@@ -724,7 +722,7 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp, u32 data)
 
 	if (state == ST_MAINLINK_READY || state == ST_DISCONNECT_PENDING) {
 		/* wait until ST_CONNECTED */
-		msm_dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 */
+		msm_dp_add_event(dp, EV_IRQ_HPD_INT, 1);
 		mutex_unlock(&dp->event_mutex);
 		return 0;
 	}
@@ -1079,7 +1077,6 @@ static int hpd_event_thread(void *data)
 			todo_next = &msm_dp_priv->event_list[msm_dp_priv->event_pndx++];
 			msm_dp_priv->event_pndx %= DP_EVENT_Q_MAX;
 			todo_next->event_id = todo->event_id;
-			todo_next->data = todo->data;
 			todo_next->delay = todo->delay - 1;
 
 			/* clean up older event */
@@ -1105,13 +1102,13 @@ static int hpd_event_thread(void *data)
 
 		switch (todo->event_id) {
 		case EV_HPD_PLUG_INT:
-			msm_dp_hpd_plug_handle(msm_dp_priv, todo->data);
+			msm_dp_hpd_plug_handle(msm_dp_priv);
 			break;
 		case EV_HPD_UNPLUG_INT:
-			msm_dp_hpd_unplug_handle(msm_dp_priv, todo->data);
+			msm_dp_hpd_unplug_handle(msm_dp_priv);
 			break;
 		case EV_IRQ_HPD_INT:
-			msm_dp_irq_hpd_handle(msm_dp_priv, todo->data);
+			msm_dp_irq_hpd_handle(msm_dp_priv);
 			break;
 		default:
 			break;
@@ -1212,19 +1209,19 @@ static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id)
 			dp->msm_dp_display.connector_type, hpd_isr_status);
 		/* hpd related interrupts */
 		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)
-			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
+			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0);
 
 		if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
-			msm_dp_add_event(dp, EV_IRQ_HPD_INT, 0, 0);
+			msm_dp_add_event(dp, EV_IRQ_HPD_INT, 0);
 		}
 
 		if (hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK) {
-			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
-			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 3);
+			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
+			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 3);
 		}
 
 		if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK)
-			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
+			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
 
 		ret = IRQ_HANDLED;
 	}
@@ -1649,7 +1646,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 	}
 
 	if (dp->is_edp)
-		msm_dp_hpd_plug_handle(msm_dp_display, 0);
+		msm_dp_hpd_plug_handle(msm_dp_display);
 
 	mutex_lock(&msm_dp_display->event_mutex);
 	if (pm_runtime_resume_and_get(&dp->pdev->dev)) {
@@ -1721,7 +1718,7 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 	msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
 
 	if (dp->is_edp)
-		msm_dp_hpd_unplug_handle(msm_dp_display, 0);
+		msm_dp_hpd_unplug_handle(msm_dp_display);
 
 	mutex_lock(&msm_dp_display->event_mutex);
 
@@ -1843,7 +1840,7 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 		return;
 
 	if (!msm_dp_display->link_ready && status == connector_status_connected)
-		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
+		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0);
 	else if (msm_dp_display->link_ready && status == connector_status_disconnected)
-		msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
+		msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
 }

-- 
2.47.3

[PATCH v4 7/9] drm/msm/dp: rework HPD handling

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

Handling of the HPD events in the MSM DP driver is plagued with lots of
problems. It tries to work aside of the main DRM framework, handling the
HPD signals on its own. There are two separate paths, one for the HPD
signals coming from the DP HPD pin and another path for signals coming
from outside (e.g. from the Type-C AltMode). It lies about the connected
state, returning the link established state instead. It is not easy to
understand or modify it. Having a separate event machine doesn't add
extra clarity.

Drop the whole event machine. When the DP receives a HPD event, send it
to the DRM core. Then handle the events in the hpd_notify callback,
unifying paths for HPD signals.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Co-developed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c    |  22 --
 drivers/gpu/drm/msm/dp/dp_ctrl.h    |   1 -
 drivers/gpu/drm/msm/dp/dp_display.c | 601 ++++++++----------------------------
 drivers/gpu/drm/msm/dp/dp_display.h |   1 -
 4 files changed, 134 insertions(+), 491 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index aa2303d0e148..80796dd255fc 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -2581,28 +2581,6 @@ void msm_dp_ctrl_off_link_stream(struct msm_dp_ctrl *msm_dp_ctrl)
 			phy, phy->init_count, phy->power_count);
 }
 
-void msm_dp_ctrl_off_link(struct msm_dp_ctrl *msm_dp_ctrl)
-{
-	struct msm_dp_ctrl_private *ctrl;
-	struct phy *phy;
-
-	ctrl = container_of(msm_dp_ctrl, struct msm_dp_ctrl_private, msm_dp_ctrl);
-	phy = ctrl->phy;
-
-	msm_dp_ctrl_mainlink_disable(ctrl);
-
-	dev_pm_opp_set_rate(ctrl->dev, 0);
-	msm_dp_ctrl_link_clk_disable(&ctrl->msm_dp_ctrl);
-
-	DRM_DEBUG_DP("Before, phy=%p init_count=%d power_on=%d\n",
-		phy, phy->init_count, phy->power_count);
-
-	phy_power_off(phy);
-
-	DRM_DEBUG_DP("After, phy=%p init_count=%d power_on=%d\n",
-		phy, phy->init_count, phy->power_count);
-}
-
 void msm_dp_ctrl_off(struct msm_dp_ctrl *msm_dp_ctrl)
 {
 	struct msm_dp_ctrl_private *ctrl;
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
index 124b9b21bb7f..f68bee62713f 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
@@ -19,7 +19,6 @@ struct phy;
 int msm_dp_ctrl_on_link(struct msm_dp_ctrl *msm_dp_ctrl);
 int msm_dp_ctrl_on_stream(struct msm_dp_ctrl *msm_dp_ctrl, bool force_link_train);
 void msm_dp_ctrl_off_link_stream(struct msm_dp_ctrl *msm_dp_ctrl);
-void msm_dp_ctrl_off_link(struct msm_dp_ctrl *msm_dp_ctrl);
 void msm_dp_ctrl_off(struct msm_dp_ctrl *msm_dp_ctrl);
 void msm_dp_ctrl_push_idle(struct msm_dp_ctrl *msm_dp_ctrl);
 irqreturn_t msm_dp_ctrl_isr(struct msm_dp_ctrl *msm_dp_ctrl);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index bc4078c229cb..e3b43d73b67a 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -43,35 +43,6 @@ enum {
 	ISR_HPD_REPLUG_COUNT,
 };
 
-/* event thread connection state */
-enum {
-	ST_DISCONNECTED,
-	ST_MAINLINK_READY,
-	ST_CONNECTED,
-	ST_DISCONNECT_PENDING,
-	ST_DISPLAY_OFF,
-};
-
-enum {
-	EV_NO_EVENT,
-	/* hpd events */
-	EV_HPD_PLUG_INT,
-	EV_IRQ_HPD_INT,
-	EV_HPD_UNPLUG_INT,
-};
-
-#define EVENT_TIMEOUT	(HZ/10)	/* 100ms */
-#define DP_EVENT_Q_MAX	8
-
-#define DP_TIMEOUT_NONE		0
-
-#define WAIT_FOR_RESUME_TIMEOUT_JIFFIES (HZ / 2)
-
-struct msm_dp_event {
-	u32 event_id;
-	u32 delay;
-};
-
 struct msm_dp_display_private {
 	int irq;
 
@@ -95,15 +66,9 @@ struct msm_dp_display_private {
 	/* wait for audio signaling */
 	struct completion audio_comp;
 
-	/* event related only access by event thread */
-	struct mutex event_mutex;
-	wait_queue_head_t event_q;
-	u32 hpd_state;
-	u32 event_pndx;
-	u32 event_gndx;
-	struct task_struct *ev_tsk;
-	struct msm_dp_event event_list[DP_EVENT_Q_MAX];
-	spinlock_t event_lock;
+	/* HPD IRQ handling */
+	spinlock_t irq_thread_lock;
+	u32 hpd_isr_status;
 
 	bool wide_bus_supported;
 
@@ -216,59 +181,6 @@ static struct msm_dp_display_private *dev_get_dp_display_private(struct device *
 	return container_of(dp, struct msm_dp_display_private, msm_dp_display);
 }
 
-static int msm_dp_add_event(struct msm_dp_display_private *msm_dp_priv, u32 event,
-			    u32 delay)
-{
-	unsigned long flag;
-	struct msm_dp_event *todo;
-	int pndx;
-
-	spin_lock_irqsave(&msm_dp_priv->event_lock, flag);
-	pndx = msm_dp_priv->event_pndx + 1;
-	pndx %= DP_EVENT_Q_MAX;
-	if (pndx == msm_dp_priv->event_gndx) {
-		pr_err("event_q is full: pndx=%d gndx=%d\n",
-			msm_dp_priv->event_pndx, msm_dp_priv->event_gndx);
-		spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-		return -EPERM;
-	}
-	todo = &msm_dp_priv->event_list[msm_dp_priv->event_pndx++];
-	msm_dp_priv->event_pndx %= DP_EVENT_Q_MAX;
-	todo->event_id = event;
-	todo->delay = delay;
-	wake_up(&msm_dp_priv->event_q);
-	spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-
-	return 0;
-}
-
-static int msm_dp_del_event(struct msm_dp_display_private *msm_dp_priv, u32 event)
-{
-	unsigned long flag;
-	struct msm_dp_event *todo;
-	u32	gndx;
-
-	spin_lock_irqsave(&msm_dp_priv->event_lock, flag);
-	if (msm_dp_priv->event_pndx == msm_dp_priv->event_gndx) {
-		spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-		return -ENOENT;
-	}
-
-	gndx = msm_dp_priv->event_gndx;
-	while (msm_dp_priv->event_pndx != gndx) {
-		todo = &msm_dp_priv->event_list[gndx];
-		if (todo->event_id == event) {
-			todo->event_id = EV_NO_EVENT;	/* deleted */
-			todo->delay = 0;
-		}
-		gndx++;
-		gndx %= DP_EVENT_Q_MAX;
-	}
-	spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-
-	return 0;
-}
-
 void msm_dp_display_signal_audio_start(struct msm_dp *msm_dp_display)
 {
 	struct msm_dp_display_private *dp;
@@ -287,8 +199,6 @@ void msm_dp_display_signal_audio_complete(struct msm_dp *msm_dp_display)
 	complete_all(&dp->audio_comp);
 }
 
-static int msm_dp_hpd_event_thread_start(struct msm_dp_display_private *msm_dp_priv);
-
 static int msm_dp_display_bind(struct device *dev, struct device *master,
 			   void *data)
 {
@@ -308,12 +218,6 @@ static int msm_dp_display_bind(struct device *dev, struct device *master,
 		goto end;
 	}
 
-	rc = msm_dp_hpd_event_thread_start(dp);
-	if (rc) {
-		DRM_ERROR("Event thread create failed\n");
-		goto end;
-	}
-
 	return 0;
 end:
 	return rc;
@@ -325,8 +229,6 @@ static void msm_dp_display_unbind(struct device *dev, struct device *master,
 	struct msm_dp_display_private *dp = dev_get_dp_display_private(dev);
 	struct msm_drm_private *priv = dev_get_drvdata(master);
 
-	kthread_stop(dp->ev_tsk);
-
 	of_dp_aux_depopulate_bus(dp->aux);
 
 	msm_dp_aux_unregister(dp->aux);
@@ -340,38 +242,6 @@ static const struct component_ops msm_dp_display_comp_ops = {
 	.unbind = msm_dp_display_unbind,
 };
 
-static int msm_dp_display_send_hpd_notification(struct msm_dp_display_private *dp,
-					    bool hpd)
-{
-	if ((hpd && dp->msm_dp_display.link_ready) ||
-			(!hpd && !dp->msm_dp_display.link_ready)) {
-		drm_dbg_dp(dp->drm_dev, "HPD already %s\n", str_on_off(hpd));
-		return 0;
-	}
-
-	/* reset video pattern flag on disconnect */
-	if (!hpd) {
-		dp->panel->video_test = false;
-		if (!dp->msm_dp_display.is_edp)
-			drm_dp_set_subconnector_property(dp->msm_dp_display.connector,
-							 connector_status_disconnected,
-							 dp->panel->dpcd,
-							 dp->panel->downstream_ports);
-	}
-
-	dp->msm_dp_display.link_ready = hpd;
-
-	drm_dbg_dp(dp->drm_dev, "type=%d hpd=%d\n",
-			dp->msm_dp_display.connector_type, hpd);
-
-	drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
-			      hpd ?
-			      connector_status_connected :
-			      connector_status_disconnected);
-
-	return 0;
-}
-
 static int msm_dp_display_lttpr_init(struct msm_dp_display_private *dp, u8 *dpcd)
 {
 	int rc, lttpr_count;
@@ -414,6 +284,8 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 						 dp->panel->dpcd,
 						 dp->panel->downstream_ports);
 
+	dp->msm_dp_display.link_ready = true;
+
 	dp->msm_dp_display.psr_supported = dp->panel->psr_cap.version && psr_enabled;
 
 	dp->audio_supported = info->has_audio;
@@ -427,8 +299,6 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 
 	msm_dp_link_reset_phy_params_vx_px(dp->link);
 
-	msm_dp_display_send_hpd_notification(dp, true);
-
 end:
 	return rc;
 }
@@ -483,24 +353,6 @@ static void msm_dp_display_host_deinit(struct msm_dp_display_private *dp)
 	dp->core_initialized = false;
 }
 
-static int msm_dp_display_usbpd_configure_cb(struct device *dev)
-{
-	struct msm_dp_display_private *dp = dev_get_dp_display_private(dev);
-
-	msm_dp_display_host_phy_init(dp);
-
-	return msm_dp_display_process_hpd_high(dp);
-}
-
-static int msm_dp_display_notify_disconnect(struct device *dev)
-{
-	struct msm_dp_display_private *dp = dev_get_dp_display_private(dev);
-
-	msm_dp_display_send_hpd_notification(dp, false);
-
-	return 0;
-}
-
 static void msm_dp_display_handle_video_request(struct msm_dp_display_private *dp)
 {
 	if (dp->link->sink_request & DP_TEST_LINK_VIDEO_PATTERN) {
@@ -509,34 +361,12 @@ static void msm_dp_display_handle_video_request(struct msm_dp_display_private *d
 	}
 }
 
-static int msm_dp_display_handle_port_status_changed(struct msm_dp_display_private *dp)
-{
-	int rc = 0;
-
-	if (drm_dp_is_branch(dp->panel->dpcd) && dp->link->sink_count == 0) {
-		drm_dbg_dp(dp->drm_dev, "sink count is zero, nothing to do\n");
-		if (dp->hpd_state != ST_DISCONNECTED) {
-			dp->hpd_state = ST_DISCONNECT_PENDING;
-			msm_dp_display_send_hpd_notification(dp, false);
-		}
-	} else {
-		if (dp->hpd_state == ST_DISCONNECTED) {
-			dp->hpd_state = ST_MAINLINK_READY;
-			rc = msm_dp_display_process_hpd_high(dp);
-			if (rc)
-				dp->hpd_state = ST_DISCONNECTED;
-		}
-	}
-
-	return rc;
-}
-
 static int msm_dp_display_handle_irq_hpd(struct msm_dp_display_private *dp)
 {
 	u32 sink_request = dp->link->sink_request;
 
 	drm_dbg_dp(dp->drm_dev, "%d\n", sink_request);
-	if (dp->hpd_state == ST_DISCONNECTED) {
+	if (!dp->msm_dp_display.link_ready) {
 		if (sink_request & DP_LINK_STATUS_UPDATED) {
 			drm_dbg_dp(dp->drm_dev, "Disconnected sink_request: %d\n",
 							sink_request);
@@ -553,76 +383,36 @@ static int msm_dp_display_handle_irq_hpd(struct msm_dp_display_private *dp)
 	return 0;
 }
 
-static int msm_dp_display_usbpd_attention_cb(struct device *dev)
-{
-	int rc = 0;
-	u32 sink_request;
-	struct msm_dp_display_private *dp = dev_get_dp_display_private(dev);
-
-	/* check for any test request issued by sink */
-	rc = msm_dp_link_process_request(dp->link);
-	if (!rc) {
-		sink_request = dp->link->sink_request;
-		drm_dbg_dp(dp->drm_dev, "hpd_state=%d sink_request=%d\n",
-					dp->hpd_state, sink_request);
-		if (sink_request & DS_PORT_STATUS_CHANGED)
-			rc = msm_dp_display_handle_port_status_changed(dp);
-		else
-			rc = msm_dp_display_handle_irq_hpd(dp);
-	}
-
-	return rc;
-}
-
 static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 {
-	u32 state;
 	int ret;
 	struct platform_device *pdev = dp->msm_dp_display.pdev;
 
-	msm_dp_aux_enable_xfers(dp->aux, true);
-
-	mutex_lock(&dp->event_mutex);
-
-	state =  dp->hpd_state;
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
-
-	if (state == ST_DISPLAY_OFF) {
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	}
-
-	if (state == ST_MAINLINK_READY || state == ST_CONNECTED) {
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	}
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
-	if (state == ST_DISCONNECT_PENDING) {
-		/* wait until ST_DISCONNECTED */
-		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 1);
-		mutex_unlock(&dp->event_mutex);
+	if (dp->msm_dp_display.link_ready)
 		return 0;
-	}
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
-		mutex_unlock(&dp->event_mutex);
 		return ret;
 	}
 
-	ret = msm_dp_display_usbpd_configure_cb(&pdev->dev);
+	msm_dp_aux_enable_xfers(dp->aux, true);
+
+	msm_dp_display_host_phy_init(dp);
+
+	ret = msm_dp_display_process_hpd_high(dp);
 	if (ret) {	/* link train failed */
-		dp->hpd_state = ST_DISCONNECTED;
+		dp->msm_dp_display.link_ready = false;
+		msm_dp_aux_enable_xfers(dp->aux, false);
 		pm_runtime_put_sync(&pdev->dev);
-	} else {
-		dp->hpd_state = ST_MAINLINK_READY;
 	}
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
-	mutex_unlock(&dp->event_mutex);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
 	/* uevent will complete connection part */
 	return 0;
@@ -644,97 +434,69 @@ static void msm_dp_display_handle_plugged_change(struct msm_dp *msm_dp_display,
 
 static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 {
-	u32 state;
 	struct platform_device *pdev = dp->msm_dp_display.pdev;
 
-	msm_dp_aux_enable_xfers(dp->aux, false);
-
-	mutex_lock(&dp->event_mutex);
-
-	state = dp->hpd_state;
+	dp->panel->video_test = false;
 
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
+	msm_dp_aux_enable_xfers(dp->aux, false);
 
-	/* unplugged, no more irq_hpd handle */
-	msm_dp_del_event(dp, EV_IRQ_HPD_INT);
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
-	if (state == ST_DISCONNECTED) {
-		/* triggered by irq_hdp with sink_count = 0 */
-		if (dp->link->sink_count == 0) {
-			msm_dp_display_host_phy_exit(dp);
-		}
-		msm_dp_display_notify_disconnect(&dp->msm_dp_display.pdev->dev);
-		mutex_unlock(&dp->event_mutex);
+	if (!dp->msm_dp_display.link_ready)
 		return 0;
-	} else if (state == ST_DISCONNECT_PENDING) {
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	} else if (state == ST_MAINLINK_READY) {
-		msm_dp_ctrl_off_link(dp->ctrl);
+
+	/* triggered by irq_hdp with sink_count = 0 */
+	if (dp->link->sink_count == 0)
 		msm_dp_display_host_phy_exit(dp);
-		dp->hpd_state = ST_DISCONNECTED;
-		msm_dp_display_notify_disconnect(&dp->msm_dp_display.pdev->dev);
-		pm_runtime_put_sync(&pdev->dev);
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	}
 
 	/*
 	 * We don't need separate work for disconnect as
 	 * connect/attention interrupts are disabled
 	 */
-	msm_dp_display_notify_disconnect(&dp->msm_dp_display.pdev->dev);
+	if (!dp->msm_dp_display.is_edp)
+		drm_dp_set_subconnector_property(dp->msm_dp_display.connector,
+						 connector_status_disconnected,
+						 dp->panel->dpcd,
+						 dp->panel->downstream_ports);
 
-	if (state == ST_DISPLAY_OFF) {
-		dp->hpd_state = ST_DISCONNECTED;
-	} else {
-		dp->hpd_state = ST_DISCONNECT_PENDING;
-	}
+	dp->msm_dp_display.link_ready = false;
 
 	/* signal the disconnect event early to ensure proper teardown */
 	msm_dp_display_handle_plugged_change(&dp->msm_dp_display, false);
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
 	/* uevent will complete disconnection part */
 	pm_runtime_put_sync(&pdev->dev);
-	mutex_unlock(&dp->event_mutex);
 	return 0;
 }
 
 static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 {
-	u32 state;
-
-	mutex_lock(&dp->event_mutex);
+	u32 sink_request;
+	int rc = 0;
 
 	/* irq_hpd can happen at either connected or disconnected state */
-	state =  dp->hpd_state;
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
-	if (state == ST_DISPLAY_OFF) {
-		mutex_unlock(&dp->event_mutex);
-		return 0;
-	}
-
-	if (state == ST_MAINLINK_READY || state == ST_DISCONNECT_PENDING) {
-		/* wait until ST_CONNECTED */
-		msm_dp_add_event(dp, EV_IRQ_HPD_INT, 1);
-		mutex_unlock(&dp->event_mutex);
-		return 0;
+	/* check for any test request issued by sink */
+	rc = msm_dp_link_process_request(dp->link);
+	if (!rc) {
+		sink_request = dp->link->sink_request;
+		drm_dbg_dp(dp->drm_dev, "sink_request=%d\n", sink_request);
+		if (sink_request & DS_PORT_STATUS_CHANGED)
+			rc = msm_dp_display_process_hpd_high(dp);
+		else
+			rc = msm_dp_display_handle_irq_hpd(dp);
 	}
 
-	msm_dp_display_usbpd_attention_cb(&dp->msm_dp_display.pdev->dev);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
+			dp->msm_dp_display.connector_type);
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d hpd_state=%d\n",
-			dp->msm_dp_display.connector_type, state);
-
-	mutex_unlock(&dp->event_mutex);
-
-	return 0;
+	return rc;
 }
 
 static void msm_dp_display_deinit_sub_modules(struct msm_dp_display_private *dp)
@@ -1010,12 +772,8 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
 	 * power_on status before dumping DP registers to avoid crash due
 	 * to unclocked access
 	 */
-	mutex_lock(&msm_dp_display->event_mutex);
-
-	if (!dp->power_on) {
-		mutex_unlock(&msm_dp_display->event_mutex);
+	if (!dp->power_on)
 		return;
-	}
 
 	msm_disp_snapshot_add_block(disp_state, msm_dp_display->ahb_len,
 				    msm_dp_display->ahb_base, "dp_ahb");
@@ -1025,8 +783,6 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
 				    msm_dp_display->link_base, "dp_link");
 	msm_disp_snapshot_add_block(disp_state, msm_dp_display->p0_len,
 				    msm_dp_display->p0_base, "dp_p0");
-
-	mutex_unlock(&msm_dp_display->event_mutex);
 }
 
 void msm_dp_display_set_psr(struct msm_dp *msm_dp_display, bool enter)
@@ -1042,95 +798,6 @@ void msm_dp_display_set_psr(struct msm_dp *msm_dp_display, bool enter)
 	msm_dp_ctrl_set_psr(dp->ctrl, enter);
 }
 
-static int hpd_event_thread(void *data)
-{
-	struct msm_dp_display_private *msm_dp_priv;
-	unsigned long flag;
-	struct msm_dp_event *todo;
-	int timeout_mode = 0;
-
-	msm_dp_priv = (struct msm_dp_display_private *)data;
-
-	while (1) {
-		if (timeout_mode) {
-			wait_event_timeout(msm_dp_priv->event_q,
-				(msm_dp_priv->event_pndx == msm_dp_priv->event_gndx) ||
-					kthread_should_stop(), EVENT_TIMEOUT);
-		} else {
-			wait_event_interruptible(msm_dp_priv->event_q,
-				(msm_dp_priv->event_pndx != msm_dp_priv->event_gndx) ||
-					kthread_should_stop());
-		}
-
-		if (kthread_should_stop())
-			break;
-
-		spin_lock_irqsave(&msm_dp_priv->event_lock, flag);
-		todo = &msm_dp_priv->event_list[msm_dp_priv->event_gndx];
-		if (todo->delay) {
-			struct msm_dp_event *todo_next;
-
-			msm_dp_priv->event_gndx++;
-			msm_dp_priv->event_gndx %= DP_EVENT_Q_MAX;
-
-			/* re enter delay event into q */
-			todo_next = &msm_dp_priv->event_list[msm_dp_priv->event_pndx++];
-			msm_dp_priv->event_pndx %= DP_EVENT_Q_MAX;
-			todo_next->event_id = todo->event_id;
-			todo_next->delay = todo->delay - 1;
-
-			/* clean up older event */
-			todo->event_id = EV_NO_EVENT;
-			todo->delay = 0;
-
-			/* switch to timeout mode */
-			timeout_mode = 1;
-			spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-			continue;
-		}
-
-		/* timeout with no events in q */
-		if (msm_dp_priv->event_pndx == msm_dp_priv->event_gndx) {
-			spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-			continue;
-		}
-
-		msm_dp_priv->event_gndx++;
-		msm_dp_priv->event_gndx %= DP_EVENT_Q_MAX;
-		timeout_mode = 0;
-		spin_unlock_irqrestore(&msm_dp_priv->event_lock, flag);
-
-		switch (todo->event_id) {
-		case EV_HPD_PLUG_INT:
-			msm_dp_hpd_plug_handle(msm_dp_priv);
-			break;
-		case EV_HPD_UNPLUG_INT:
-			msm_dp_hpd_unplug_handle(msm_dp_priv);
-			break;
-		case EV_IRQ_HPD_INT:
-			msm_dp_irq_hpd_handle(msm_dp_priv);
-			break;
-		default:
-			break;
-		}
-	}
-
-	return 0;
-}
-
-static int msm_dp_hpd_event_thread_start(struct msm_dp_display_private *msm_dp_priv)
-{
-	/* set event q to empty */
-	msm_dp_priv->event_gndx = 0;
-	msm_dp_priv->event_pndx = 0;
-
-	msm_dp_priv->ev_tsk = kthread_run(hpd_event_thread, msm_dp_priv, "dp_hpd_handler");
-	if (IS_ERR(msm_dp_priv->ev_tsk))
-		return PTR_ERR(msm_dp_priv->ev_tsk);
-
-	return 0;
-}
-
 /**
  * msm_dp_bridge_detect - callback to determine if connector is connected
  * @bridge: Pointer to drm bridge structure
@@ -1155,26 +822,31 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 	if (!dp->link_ready)
 		return status;
 
-	msm_dp_aux_enable_xfers(priv->aux, true);
-
 	ret = pm_runtime_resume_and_get(&dp->pdev->dev);
 	if (ret) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
-		msm_dp_aux_enable_xfers(priv->aux, false);
 		return status;
 	}
 
+	msm_dp_aux_enable_xfers(priv->aux, true);
+
 	ret = msm_dp_aux_is_link_connected(priv->aux);
-	if (dp->internal_hpd && !ret)
+	if (!ret) {
+		DRM_DEBUG_DP("aux not connected\n");
 		goto end;
+	}
 
 	ret = drm_dp_read_dpcd_caps(priv->aux, dpcd);
-	if (ret)
+	if (ret) {
+		DRM_DEBUG_DP("failed to read caps\n");
 		goto end;
+	}
 
 	ret = drm_dp_read_desc(priv->aux, &desc, drm_dp_is_branch(dpcd));
-	if (ret)
+	if (ret) {
+		DRM_DEBUG_DP("failed to read desc\n");
 		goto end;
+	}
 
 	status = connector_status_connected;
 	if (drm_dp_read_sink_count_cap(connector, dpcd, &desc)) {
@@ -1194,36 +866,20 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id)
 {
 	struct msm_dp_display_private *dp = dev_id;
-	irqreturn_t ret = IRQ_NONE;
 	u32 hpd_isr_status;
-
-	if (!dp) {
-		DRM_ERROR("invalid data\n");
-		return IRQ_NONE;
-	}
+	unsigned long flags;
+	irqreturn_t ret = IRQ_HANDLED;
 
 	hpd_isr_status = msm_dp_aux_get_hpd_intr_status(dp->aux);
 
 	if (hpd_isr_status & 0x0F) {
 		drm_dbg_dp(dp->drm_dev, "type=%d isr=0x%x\n",
 			dp->msm_dp_display.connector_type, hpd_isr_status);
-		/* hpd related interrupts */
-		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)
-			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0);
-
-		if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
-			msm_dp_add_event(dp, EV_IRQ_HPD_INT, 0);
-		}
 
-		if (hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK) {
-			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
-			msm_dp_add_event(dp, EV_HPD_PLUG_INT, 3);
-		}
-
-		if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK)
-			msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
-
-		ret = IRQ_HANDLED;
+		spin_lock_irqsave(&dp->irq_thread_lock, flags);
+		dp->hpd_isr_status |= hpd_isr_status;
+		ret = IRQ_WAKE_THREAD;
+		spin_unlock_irqrestore(&dp->irq_thread_lock, flags);
 	}
 
 	/* DP controller isr */
@@ -1232,6 +888,36 @@ static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id)
 	return ret;
 }
 
+static irqreturn_t msm_dp_display_irq_thread(int irq, void *dev_id)
+{
+	struct msm_dp_display_private *dp = dev_id;
+	irqreturn_t ret = IRQ_NONE;
+	unsigned long flags;
+	u32 hpd_isr_status;
+
+	spin_lock_irqsave(&dp->irq_thread_lock, flags);
+	hpd_isr_status = dp->hpd_isr_status;
+	dp->hpd_isr_status = 0;
+	spin_unlock_irqrestore(&dp->irq_thread_lock, flags);
+
+	if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK)
+		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
+				      connector_status_disconnected);
+
+	if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)
+		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
+				      connector_status_connected);
+
+	/* Send HPD as connected and distinguish it in the notifier */
+	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK)
+		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
+				      connector_status_connected);
+
+	ret = IRQ_HANDLED;
+
+	return ret;
+}
+
 static int msm_dp_display_request_irq(struct msm_dp_display_private *dp)
 {
 	int rc = 0;
@@ -1243,9 +929,13 @@ static int msm_dp_display_request_irq(struct msm_dp_display_private *dp)
 		return dp->irq;
 	}
 
-	rc = devm_request_irq(&pdev->dev, dp->irq, msm_dp_display_irq_handler,
-			      IRQF_TRIGGER_HIGH|IRQF_NO_AUTOEN,
-			      "dp_display_isr", dp);
+	spin_lock_init(&dp->irq_thread_lock);
+	irq_set_status_flags(dp->irq, IRQ_NOAUTOEN);
+	rc = devm_request_threaded_irq(&pdev->dev, dp->irq,
+				       msm_dp_display_irq_handler,
+				       msm_dp_display_irq_thread,
+				       IRQ_TYPE_LEVEL_HIGH,
+				       "dp_display_isr", dp);
 
 	if (rc < 0) {
 		DRM_ERROR("failed to request IRQ%u: %d\n",
@@ -1425,6 +1115,7 @@ static int msm_dp_display_probe(struct platform_device *pdev)
 	dp->wide_bus_supported = desc->wide_bus_supported;
 	dp->msm_dp_display.is_edp =
 		(dp->msm_dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
+	dp->hpd_isr_status = 0;
 
 	rc = msm_dp_display_get_io(dp);
 	if (rc)
@@ -1436,11 +1127,6 @@ static int msm_dp_display_probe(struct platform_device *pdev)
 		return -EPROBE_DEFER;
 	}
 
-	/* setup event q */
-	mutex_init(&dp->event_mutex);
-	init_waitqueue_head(&dp->event_q);
-	spin_lock_init(&dp->event_lock);
-
 	/* Store DP audio handle inside DP display */
 	dp->msm_dp_display.msm_dp_audio = dp->audio;
 
@@ -1636,7 +1322,6 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 	struct msm_dp *dp = msm_dp_bridge->msm_dp_display;
 	int rc = 0;
 	struct msm_dp_display_private *msm_dp_display;
-	u32 hpd_state;
 	bool force_link_train = false;
 
 	msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
@@ -1648,29 +1333,21 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 	if (dp->is_edp)
 		msm_dp_hpd_plug_handle(msm_dp_display);
 
-	mutex_lock(&msm_dp_display->event_mutex);
 	if (pm_runtime_resume_and_get(&dp->pdev->dev)) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
-		mutex_unlock(&msm_dp_display->event_mutex);
 		return;
 	}
 
-	hpd_state = msm_dp_display->hpd_state;
-	if (hpd_state != ST_DISPLAY_OFF && hpd_state != ST_MAINLINK_READY) {
-		mutex_unlock(&msm_dp_display->event_mutex);
+	if (msm_dp_display->link->sink_count == 0)
 		return;
-	}
 
 	rc = msm_dp_display_set_mode(dp, &msm_dp_display->msm_dp_mode);
 	if (rc) {
 		DRM_ERROR("Failed to perform a mode set, rc=%d\n", rc);
-		mutex_unlock(&msm_dp_display->event_mutex);
 		return;
 	}
 
-	hpd_state =  msm_dp_display->hpd_state;
-
-	if (hpd_state == ST_DISPLAY_OFF) {
+	if (dp->link_ready && !dp->power_on) {
 		msm_dp_display_host_phy_init(msm_dp_display);
 		force_link_train = true;
 	}
@@ -1688,11 +1365,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		msm_dp_display_disable(msm_dp_display);
 	}
 
-	/* completed connection */
-	msm_dp_display->hpd_state = ST_CONNECTED;
-
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
-	mutex_unlock(&msm_dp_display->event_mutex);
 }
 
 void msm_dp_bridge_atomic_disable(struct drm_bridge *drm_bridge,
@@ -1712,7 +1385,6 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 {
 	struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(drm_bridge);
 	struct msm_dp *dp = msm_dp_bridge->msm_dp_display;
-	u32 hpd_state;
 	struct msm_dp_display_private *msm_dp_display;
 
 	msm_dp_display = container_of(dp, struct msm_dp_display_private, msm_dp_display);
@@ -1720,27 +1392,14 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 	if (dp->is_edp)
 		msm_dp_hpd_unplug_handle(msm_dp_display);
 
-	mutex_lock(&msm_dp_display->event_mutex);
-
-	hpd_state = msm_dp_display->hpd_state;
-	if (hpd_state != ST_DISCONNECT_PENDING && hpd_state != ST_CONNECTED)
-		drm_dbg_dp(dp->drm_dev, "type=%d wrong hpd_state=%d\n",
-			   dp->connector_type, hpd_state);
+	if (!dp->link_ready)
+		drm_dbg_dp(dp->drm_dev, "type=%d is disconnected\n", dp->connector_type);
 
 	msm_dp_display_disable(msm_dp_display);
 
-	hpd_state =  msm_dp_display->hpd_state;
-	if (hpd_state == ST_DISCONNECT_PENDING) {
-		/* completed disconnection */
-		msm_dp_display->hpd_state = ST_DISCONNECTED;
-	} else {
-		msm_dp_display->hpd_state = ST_DISPLAY_OFF;
-	}
-
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
 
 	pm_runtime_put_sync(&dp->pdev->dev);
-	mutex_unlock(&msm_dp_display->event_mutex);
 }
 
 void msm_dp_bridge_mode_set(struct drm_bridge *drm_bridge,
@@ -1796,18 +1455,13 @@ void msm_dp_bridge_hpd_enable(struct drm_bridge *bridge)
 	 * step-4: DP PHY is initialized at plugin handler before link training
 	 *
 	 */
-	mutex_lock(&dp->event_mutex);
 	if (pm_runtime_resume_and_get(&msm_dp_display->pdev->dev)) {
 		DRM_ERROR("failed to resume power\n");
-		mutex_unlock(&dp->event_mutex);
 		return;
 	}
 
 	msm_dp_aux_hpd_enable(dp->aux);
 	msm_dp_aux_hpd_intr_enable(dp->aux);
-
-	msm_dp_display->internal_hpd = true;
-	mutex_unlock(&dp->event_mutex);
 }
 
 void msm_dp_bridge_hpd_disable(struct drm_bridge *bridge)
@@ -1816,15 +1470,10 @@ void msm_dp_bridge_hpd_disable(struct drm_bridge *bridge)
 	struct msm_dp *msm_dp_display = msm_dp_bridge->msm_dp_display;
 	struct msm_dp_display_private *dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
 
-	mutex_lock(&dp->event_mutex);
-
 	msm_dp_aux_hpd_intr_disable(dp->aux);
 	msm_dp_aux_hpd_disable(dp->aux);
 
-	msm_dp_display->internal_hpd = false;
-
 	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
-	mutex_unlock(&dp->event_mutex);
 }
 
 void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
@@ -1834,13 +1483,31 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 	struct msm_dp_bridge *msm_dp_bridge = to_dp_bridge(bridge);
 	struct msm_dp *msm_dp_display = msm_dp_bridge->msm_dp_display;
 	struct msm_dp_display_private *dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
+	u32 hpd_link_status = 0;
 
-	/* Without next_bridge interrupts are handled by the DP core directly */
-	if (msm_dp_display->internal_hpd)
+	if (pm_runtime_resume_and_get(&msm_dp_display->pdev->dev)) {
+		DRM_ERROR("failed to pm_runtime_resume\n");
 		return;
+	}
+
+	hpd_link_status = msm_dp_aux_is_link_connected(dp->aux);
 
-	if (!msm_dp_display->link_ready && status == connector_status_connected)
-		msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0);
-	else if (msm_dp_display->link_ready && status == connector_status_disconnected)
-		msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0);
+	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, link_ready=%d, status=%d\n",
+		   msm_dp_display->connector_type, hpd_link_status,
+		   msm_dp_display->link_ready, status);
+
+	if (status == connector_status_connected) {
+		if (hpd_link_status == ISR_HPD_REPLUG_COUNT) {
+			msm_dp_hpd_plug_handle(dp);
+			msm_dp_hpd_unplug_handle(dp);
+		} else if (hpd_link_status == ISR_IRQ_HPD_PULSE_COUNT) {
+			msm_dp_irq_hpd_handle(dp);
+		} else {
+			msm_dp_hpd_plug_handle(dp);
+		}
+	} else {
+		msm_dp_hpd_unplug_handle(dp);
+	}
+
+	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
 }
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 60094061c102..d2d3d61eb0b0 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -22,7 +22,6 @@ struct msm_dp {
 	bool power_on;
 	unsigned int connector_type;
 	bool is_edp;
-	bool internal_hpd;
 
 	struct msm_dp_audio *msm_dp_audio;
 	bool psr_supported;

-- 
2.47.3

[PATCH v4 8/9] drm/msm/dp: Add sink_count to debug logs

[Dmitry Baryshkov]

From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>

Add sink count to the debug logs for [un]plug and HPD IRQ handling.

Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
[DB: dropped link_ready handling]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index e3b43d73b67a..a1fb9c62bb0e 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -388,8 +388,9 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 	int ret;
 	struct platform_device *pdev = dp->msm_dp_display.pdev;
 
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	if (dp->msm_dp_display.link_ready)
 		return 0;
@@ -411,8 +412,9 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 		pm_runtime_put_sync(&pdev->dev);
 	}
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	/* uevent will complete connection part */
 	return 0;
@@ -440,8 +442,9 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 
 	msm_dp_aux_enable_xfers(dp->aux, false);
 
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	if (!dp->msm_dp_display.link_ready)
 		return 0;
@@ -465,8 +468,9 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 	/* signal the disconnect event early to ensure proper teardown */
 	msm_dp_display_handle_plugged_change(&dp->msm_dp_display, false);
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d, sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	/* uevent will complete disconnection part */
 	pm_runtime_put_sync(&pdev->dev);
@@ -479,8 +483,9 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 	int rc = 0;
 
 	/* irq_hpd can happen at either connected or disconnected state */
-	drm_dbg_dp(dp->drm_dev, "Before, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "Before, type=%d, sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	/* check for any test request issued by sink */
 	rc = msm_dp_link_process_request(dp->link);
@@ -493,8 +498,9 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp)
 			rc = msm_dp_display_handle_irq_hpd(dp);
 	}
 
-	drm_dbg_dp(dp->drm_dev, "After, type=%d\n",
-			dp->msm_dp_display.connector_type);
+	drm_dbg_dp(dp->drm_dev, "After, type=%d, sink_count=%d\n",
+			dp->msm_dp_display.connector_type,
+			dp->link->sink_count);
 
 	return rc;
 }

-- 
2.47.3

[PATCH v4 9/9] drm/msm/dp: turn link_ready into plugged

[Dmitry Baryshkov]

Tracking when the DP link is ready isn't that useful from the driver
point of view. It doesn't provide a direct information if the device
should be suspended, etc. Replace it with the 'plugged' boolean, which
is set when the driver knows that there is DPRX plugged.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 94 ++++++++++++++++++++++---------------
 drivers/gpu/drm/msm/dp/dp_display.h |  1 -
 drivers/gpu/drm/msm/dp/dp_drm.c     | 41 ++--------------
 3 files changed, 61 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index a1fb9c62bb0e..4e3664f9e5e5 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -53,6 +53,9 @@ struct msm_dp_display_private {
 	bool phy_initialized;
 	bool audio_supported;
 
+	struct mutex plugged_lock;
+	bool plugged;
+
 	struct drm_device *drm_dev;
 
 	struct drm_dp_aux *aux;
@@ -284,8 +287,6 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 						 dp->panel->dpcd,
 						 dp->panel->downstream_ports);
 
-	dp->msm_dp_display.link_ready = true;
-
 	dp->msm_dp_display.psr_supported = dp->panel->psr_cap.version && psr_enabled;
 
 	dp->audio_supported = info->has_audio;
@@ -303,7 +304,7 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
 	return rc;
 }
 
-static void msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
+static bool msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
 {
 	drm_dbg_dp(dp->drm_dev, "type=%d core_init=%d phy_init=%d\n",
 		dp->msm_dp_display.connector_type, dp->core_initialized,
@@ -312,7 +313,10 @@ static void msm_dp_display_host_phy_init(struct msm_dp_display_private *dp)
 	if (!dp->phy_initialized) {
 		msm_dp_ctrl_phy_init(dp->ctrl);
 		dp->phy_initialized = true;
+		return true;
 	}
+
+	return false;
 }
 
 static void msm_dp_display_host_phy_exit(struct msm_dp_display_private *dp)
@@ -366,14 +370,6 @@ static int msm_dp_display_handle_irq_hpd(struct msm_dp_display_private *dp)
 	u32 sink_request = dp->link->sink_request;
 
 	drm_dbg_dp(dp->drm_dev, "%d\n", sink_request);
-	if (!dp->msm_dp_display.link_ready) {
-		if (sink_request & DP_LINK_STATUS_UPDATED) {
-			drm_dbg_dp(dp->drm_dev, "Disconnected sink_request: %d\n",
-							sink_request);
-			DRM_ERROR("Disconnected, no DP_LINK_STATUS_UPDATED\n");
-			return -EINVAL;
-		}
-	}
 
 	msm_dp_ctrl_handle_sink_request(dp->ctrl);
 
@@ -392,11 +388,11 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	if (dp->msm_dp_display.link_ready)
-		return 0;
+	mutex_lock(&dp->plugged_lock);
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret) {
+		mutex_unlock(&dp->plugged_lock);
 		DRM_ERROR("failed to pm_runtime_resume\n");
 		return ret;
 	}
@@ -406,18 +402,16 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp)
 	msm_dp_display_host_phy_init(dp);
 
 	ret = msm_dp_display_process_hpd_high(dp);
-	if (ret) {	/* link train failed */
-		dp->msm_dp_display.link_ready = false;
-		msm_dp_aux_enable_xfers(dp->aux, false);
-		pm_runtime_put_sync(&pdev->dev);
-	}
 
 	drm_dbg_dp(dp->drm_dev, "After, type=%d sink_count=%d\n",
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	/* uevent will complete connection part */
-	return 0;
+	dp->plugged = true;
+
+	mutex_unlock(&dp->plugged_lock);
+
+	return ret;
 };
 
 static void msm_dp_display_handle_plugged_change(struct msm_dp *msm_dp_display,
@@ -446,8 +440,12 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	if (!dp->msm_dp_display.link_ready)
+	mutex_lock(&dp->plugged_lock);
+	if (!dp->plugged) {
+		mutex_unlock(&dp->plugged_lock);
+
 		return 0;
+	}
 
 	/* triggered by irq_hdp with sink_count = 0 */
 	if (dp->link->sink_count == 0)
@@ -463,8 +461,6 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 						 dp->panel->dpcd,
 						 dp->panel->downstream_ports);
 
-	dp->msm_dp_display.link_ready = false;
-
 	/* signal the disconnect event early to ensure proper teardown */
 	msm_dp_display_handle_plugged_change(&dp->msm_dp_display, false);
 
@@ -472,8 +468,12 @@ static int msm_dp_hpd_unplug_handle(struct msm_dp_display_private *dp)
 			dp->msm_dp_display.connector_type,
 			dp->link->sink_count);
 
-	/* uevent will complete disconnection part */
-	pm_runtime_put_sync(&pdev->dev);
+	if (dp->plugged) {
+		pm_runtime_put_sync(&pdev->dev);
+		dp->plugged = false;
+	}
+	mutex_unlock(&dp->plugged_lock);
+
 	return 0;
 }
 
@@ -820,41 +820,49 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 	int status = connector_status_disconnected;
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
 	struct drm_dp_desc desc;
+	bool phy_deinit;
 
 	dp = to_dp_bridge(bridge)->msm_dp_display;
 
 	priv = container_of(dp, struct msm_dp_display_private, msm_dp_display);
 
-	if (!dp->link_ready)
-		return status;
-
+	mutex_lock(&priv->plugged_lock);
 	ret = pm_runtime_resume_and_get(&dp->pdev->dev);
 	if (ret) {
 		DRM_ERROR("failed to pm_runtime_resume\n");
+		mutex_unlock(&priv->plugged_lock);
 		return status;
 	}
 
+	phy_deinit = msm_dp_display_host_phy_init(priv);
+
 	msm_dp_aux_enable_xfers(priv->aux, true);
 
 	ret = msm_dp_aux_is_link_connected(priv->aux);
-	if (!ret) {
+	DRM_DEBUG_DP("aux link status: %x\n", ret);
+	if (!priv->plugged && !ret) {
 		DRM_DEBUG_DP("aux not connected\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	ret = drm_dp_read_dpcd_caps(priv->aux, dpcd);
 	if (ret) {
 		DRM_DEBUG_DP("failed to read caps\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	ret = drm_dp_read_desc(priv->aux, &desc, drm_dp_is_branch(dpcd));
 	if (ret) {
 		DRM_DEBUG_DP("failed to read desc\n");
+		priv->plugged = false;
 		goto end;
 	}
 
 	status = connector_status_connected;
+	priv->plugged = true;
+
 	if (drm_dp_read_sink_count_cap(connector, dpcd, &desc)) {
 		int sink_count = drm_dp_read_sink_count(priv->aux);
 
@@ -865,7 +873,21 @@ enum drm_connector_status msm_dp_bridge_detect(struct drm_bridge *bridge,
 	}
 
 end:
-	pm_runtime_put_sync(&dp->pdev->dev);
+	/*
+	 * If we detected the DPRX, leave the controller on so that it doesn't
+	 * loose the state.
+	 */
+	if (!priv->plugged) {
+		if (phy_deinit) {
+			msm_dp_aux_enable_xfers(priv->aux, false);
+			msm_dp_display_host_phy_exit(priv);
+		}
+
+		pm_runtime_put_sync(&dp->pdev->dev);
+	}
+
+	mutex_unlock(&priv->plugged_lock);
+
 	return status;
 }
 
@@ -1123,6 +1145,8 @@ static int msm_dp_display_probe(struct platform_device *pdev)
 		(dp->msm_dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
 	dp->hpd_isr_status = 0;
 
+	mutex_init(&dp->plugged_lock);
+
 	rc = msm_dp_display_get_io(dp);
 	if (rc)
 		return rc;
@@ -1353,7 +1377,7 @@ void msm_dp_bridge_atomic_enable(struct drm_bridge *drm_bridge,
 		return;
 	}
 
-	if (dp->link_ready && !dp->power_on) {
+	if (!dp->power_on) {
 		msm_dp_display_host_phy_init(msm_dp_display);
 		force_link_train = true;
 	}
@@ -1398,9 +1422,6 @@ void msm_dp_bridge_atomic_post_disable(struct drm_bridge *drm_bridge,
 	if (dp->is_edp)
 		msm_dp_hpd_unplug_handle(msm_dp_display);
 
-	if (!dp->link_ready)
-		drm_dbg_dp(dp->drm_dev, "type=%d is disconnected\n", dp->connector_type);
-
 	msm_dp_display_disable(msm_dp_display);
 
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", dp->connector_type);
@@ -1498,9 +1519,8 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
 
 	hpd_link_status = msm_dp_aux_is_link_connected(dp->aux);
 
-	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, link_ready=%d, status=%d\n",
-		   msm_dp_display->connector_type, hpd_link_status,
-		   msm_dp_display->link_ready, status);
+	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, status=%d\n",
+		   msm_dp_display->connector_type, hpd_link_status, status);
 
 	if (status == connector_status_connected) {
 		if (hpd_link_status == ISR_HPD_REPLUG_COUNT) {
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index d2d3d61eb0b0..0b65e16c790d 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -17,7 +17,6 @@ struct msm_dp {
 	struct drm_connector *connector;
 	struct drm_bridge *next_bridge;
 	struct drm_bridge *bridge;
-	bool link_ready;
 	bool audio_enabled;
 	bool power_on;
 	unsigned int connector_type;
diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index f935093c4df4..8dc0dabd275c 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -15,36 +15,6 @@
 #include "dp_audio.h"
 #include "dp_drm.h"
 
-static int msm_dp_bridge_atomic_check(struct drm_bridge *bridge,
-			    struct drm_bridge_state *bridge_state,
-			    struct drm_crtc_state *crtc_state,
-			    struct drm_connector_state *conn_state)
-{
-	struct msm_dp *dp;
-
-	dp = to_dp_bridge(bridge)->msm_dp_display;
-
-	drm_dbg_dp(dp->drm_dev, "link_ready = %s\n",
-		str_true_false(dp->link_ready));
-
-	/*
-	 * There is no protection in the DRM framework to check if the display
-	 * pipeline has been already disabled before trying to disable it again.
-	 * Hence if the sink is unplugged, the pipeline gets disabled, but the
-	 * crtc->active is still true. Any attempt to set the mode or manually
-	 * disable this encoder will result in the crash.
-	 *
-	 * TODO: add support for telling the DRM subsystem that the pipeline is
-	 * disabled by the hardware and thus all access to it should be forbidden.
-	 * After that this piece of code can be removed.
-	 */
-	if (bridge->ops & DRM_BRIDGE_OP_HPD)
-		return (dp->link_ready) ? 0 : -ENOTCONN;
-
-	return 0;
-}
-
-
 /**
  * msm_dp_bridge_get_modes - callback to add drm modes via drm_mode_probed_add()
  * @bridge: Poiner to drm bridge
@@ -62,12 +32,10 @@ static int msm_dp_bridge_get_modes(struct drm_bridge *bridge, struct drm_connect
 	dp = to_dp_bridge(bridge)->msm_dp_display;
 
 	/* pluggable case assumes EDID is read when HPD */
-	if (dp->link_ready) {
-		rc = msm_dp_display_get_modes(dp);
-		if (rc <= 0) {
-			DRM_ERROR("failed to get DP sink modes, rc=%d\n", rc);
-			return rc;
-		}
+	rc = msm_dp_display_get_modes(dp);
+	if (rc <= 0) {
+		DRM_ERROR("failed to get DP sink modes, rc=%d\n", rc);
+		return rc;
 	} else {
 		drm_dbg_dp(connector->dev, "No sink connected\n");
 	}
@@ -92,7 +60,6 @@ static const struct drm_bridge_funcs msm_dp_bridge_ops = {
 	.mode_valid   = msm_dp_bridge_mode_valid,
 	.get_modes    = msm_dp_bridge_get_modes,
 	.detect       = msm_dp_bridge_detect,
-	.atomic_check = msm_dp_bridge_atomic_check,
 	.hpd_enable   = msm_dp_bridge_hpd_enable,
 	.hpd_disable  = msm_dp_bridge_hpd_disable,
 	.hpd_notify   = msm_dp_bridge_hpd_notify,

-- 
2.47.3

Re: [PATCH v4 0/9] drm/msm/dp: Drop the HPD state machine

[Konrad Dybcio]

On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> Currently, all HPD interrupt handling must go through the HPD state
> machine.
> 
> This has caused many issues where the DRM framework assumes that DP is
> in one state while the state machine is stuck in another state.
> 
> As discussed here [1], this series:
> 
> - Removes the state machine
> - Moves link training to atomic_enable()
> - Changes the detect() behavior to return true if a display is physically
>   plugged in (as opposed to if the DP link is ready).
> - Remove event queue and move internal HPD handling to hpd_notify()
> 
> Note: eDP is mostly untested. This will be sorted out before the next
> iteration, but it will not affect the series in a major way.
> 
> Note 2: there is an issue with the DP connectors using GPIO for HPD
> (rather than using the nativate DP HPD pin), the DP will not detect a
> display if it is plugged in before the board is booted. This is not an
> issue of this series and it will be handled by a separate series to be
> posted today or tomorrow.
> 
> [1] https://patchwork.freedesktop.org/patch/656312/?series=142010&rev=2#comment_1201738
> 
> ---
> Changes in v4:
> - Fixed PM runtime handling
> - Fixed several cases where the HPD machine would loose its state
> - Fixed the case where detection was ignoring the plugging in display.

- forgot to run b4 trailers -u

(no worries though)

Konrad

Re: [PATCH v4 1/9] drm/msm/dp: fix HPD state status bit shift value

[Konrad Dybcio]

On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> 
> The HPD state status is the 3 most significant bits, not 4 bits of the
> HPD_INT_STATUS register.
> 
> Fix the bit shift macro so that the correct bits are returned in
> msm_dp_aux_is_link_connected().
> 
> Fixes: 19e52bcb27c2 ("drm/msm/dp: return correct connection status after suspend")
> Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

Re: [PATCH v4 2/9] drm/msm/dp: Fix the ISR_* enum values

[Konrad Dybcio]

On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> 
> The ISR_HPD_* enum should represent values that can be read from the
> REG_DP_DP_HPD_INT_STATUS register. Swap ISR_HPD_IO_GLITCH_COUNT and
> ISR_HPD_REPLUG_COUNT to map them correctly to register values.
> 
> While we are at it, correct the spelling for ISR_HPD_REPLUG_COUNT.
> 
> Fixes: 8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
> Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

Re: [PATCH v4 0/9] drm/msm/dp: Drop the HPD state machine

[Dmitry Baryshkov]

On Mon, Mar 09, 2026 at 01:45:34PM +0100, Konrad Dybcio wrote:
> On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> > Currently, all HPD interrupt handling must go through the HPD state
> > machine.
> > 
> > This has caused many issues where the DRM framework assumes that DP is
> > in one state while the state machine is stuck in another state.
> > 
> > As discussed here [1], this series:
> > 
> > - Removes the state machine
> > - Moves link training to atomic_enable()
> > - Changes the detect() behavior to return true if a display is physically
> >   plugged in (as opposed to if the DP link is ready).
> > - Remove event queue and move internal HPD handling to hpd_notify()
> > 
> > Note: eDP is mostly untested. This will be sorted out before the next
> > iteration, but it will not affect the series in a major way.
> > 
> > Note 2: there is an issue with the DP connectors using GPIO for HPD
> > (rather than using the nativate DP HPD pin), the DP will not detect a
> > display if it is plugged in before the board is booted. This is not an
> > issue of this series and it will be handled by a separate series to be
> > posted today or tomorrow.
> > 
> > [1] https://patchwork.freedesktop.org/patch/656312/?series=142010&rev=2#comment_1201738
> > 
> > ---
> > Changes in v4:
> > - Fixed PM runtime handling
> > - Fixed several cases where the HPD machine would loose its state
> > - Fixed the case where detection was ignoring the plugging in display.
> 
> - forgot to run b4 trailers -u

Mea culpa!

> 
> (no worries though)
> 
> Konrad

-- 
With best wishes
Dmitry

Re: [PATCH v4 5/9] drm/msm/dp: Drop EV_USER_NOTIFICATION

[Konrad Dybcio]

On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> From: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> 
> Currently, we queue an event for signalling HPD connect/disconnect. This
> can mean a delay in plug/unplug handling and notifying DRM core when a
> hotplug happens.
> 
> Drop EV_USER_NOTIFICATION and signal the IRQ event as part of hotplug
> handling.
> 
> Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---

Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

Re: [PATCH v4 6/9] drm/msm/dp: drop event data

[Konrad Dybcio]

On 3/5/26 3:30 PM, Dmitry Baryshkov wrote:
> With EV_USER_NOTIFICATION gone event's data is no longer useful. Drop
> it, removing also the argument from event handlers.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad