linux-kernel - [PATCH] drm/bridge: anx7625: Ensure bridge is suspended in disable()

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Date: Wed, 17 Jan 2024 17:58:14 -0800
From: Hsin-Yi Wang <hsinyi@...omium.org>
To: Douglas Anderson <dianders@...omium.org>,
	dri-devel@...ts.freedesktop.org
Cc: Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Daniel Vetter <daniel@...ll.ch>,
	Xin Ji <xji@...logixsemi.com>,
	Pin-yen Lin <treapking@...omium.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm/bridge: anx7625: Ensure bridge is suspended in disable()

Similar to commit 26db46bc9c67 ("drm/bridge: parade-ps8640: Ensure bridge
is suspended in .post_disable()"). Add a mutex to ensure that aux transfer
won't race with atomic_disable by holding the PM reference and prevent
the bridge from suspend.

Also we need to use pm_runtime_put_sync_suspend() to suspend the bridge
instead of idle with pm_runtime_put_sync().

Fixes: 3203e497eb76 ("drm/bridge: anx7625: Synchronously run runtime suspend.")
Fixes: adca62ec370c ("drm/bridge: anx7625: Support reading edid through aux channel")
Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
Tested-by: Xuxin Xiong <xuxinxiong@...qin.corp-partner.google.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 7 ++++++-
 drivers/gpu/drm/bridge/analogix/anx7625.h | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index ef31033439bc..29d91493b101 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1762,6 +1762,7 @@ static ssize_t anx7625_aux_transfer(struct drm_dp_aux *aux,
 	u8 request = msg->request & ~DP_AUX_I2C_MOT;
 	int ret = 0;
 
+	mutex_lock(&ctx->aux_lock);
 	pm_runtime_get_sync(dev);
 	msg->reply = 0;
 	switch (request) {
@@ -1778,6 +1779,7 @@ static ssize_t anx7625_aux_transfer(struct drm_dp_aux *aux,
 					msg->size, msg->buffer);
 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);
+	mutex_unlock(&ctx->aux_lock);
 
 	return ret;
 }
@@ -2474,7 +2476,9 @@ static void anx7625_bridge_atomic_disable(struct drm_bridge *bridge,
 	ctx->connector = NULL;
 	anx7625_dp_stop(ctx);
 
-	pm_runtime_put_sync(dev);
+	mutex_lock(&ctx->aux_lock);
+	pm_runtime_put_sync_suspend(dev);
+	mutex_unlock(&ctx->aux_lock);
 }
 
 static enum drm_connector_status
@@ -2668,6 +2672,7 @@ static int anx7625_i2c_probe(struct i2c_client *client)
 
 	mutex_init(&platform->lock);
 	mutex_init(&platform->hdcp_wq_lock);
+	mutex_init(&platform->aux_lock);
 
 	INIT_DELAYED_WORK(&platform->hdcp_work, hdcp_check_work_func);
 	platform->hdcp_workqueue = create_workqueue("hdcp workqueue");
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
index 66ebee7f3d83..39ed35d33836 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.h
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
@@ -475,6 +475,8 @@ struct anx7625_data {
 	struct workqueue_struct *hdcp_workqueue;
 	/* Lock for hdcp work queue */
 	struct mutex hdcp_wq_lock;
+	/* Lock for aux transfer and disable */
+	struct mutex aux_lock;
 	char edid_block;
 	struct display_timing dt;
 	u8 display_timing_valid;
-- 
2.43.0.381.gb435a96ce8-goog