diff mbox series

[v4,3/3] drm/bridge/lontium-lt9611uxc: move HPD notification out of IRQ handler

Message ID 20210121233303.1221784-4-dmitry.baryshkov@linaro.org
State Accepted
Commit bc6fa8676ebbf9c5285f80d7b831663aeabb90bb
Headers show
Series drm/bridge/lontium-lt9611uxc: fix handling of EDID/HPD | expand

Commit Message

Dmitry Baryshkov Jan. 21, 2021, 11:33 p.m. UTC 
drm hotplug handling code (drm_client_dev_hotplug()) can wait on mutex,
thus delaying further lt9611uxc IRQ events processing.  It was observed
occasionally during bootups, when drm_client_modeset_probe() was waiting
for EDID ready event, which was delayed because IRQ handler was stuck
trying to deliver hotplug event.
Move hotplug notifications from IRQ handler to separate work to be able
to process IRQ events without delays.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Fixes: 0cbbd5b1a012 ("drm: bridge: add support for lontium LT9611UXC bridge")
---
 drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 46 +++++++++++++++++-----
 1 file changed, 37 insertions(+), 9 deletions(-)

-- 
2.29.2

Comments

Andrzej Hajda Jan. 28, 2021, 11:24 a.m. UTC | #1 
W dniu 22.01.2021 o 10:34, Andrzej Hajda pisze:
> W dniu 22.01.2021 o 00:33, Dmitry Baryshkov pisze:
>> drm hotplug handling code (drm_client_dev_hotplug()) can wait on mutex,
>> thus delaying further lt9611uxc IRQ events processing.  It was observed
>> occasionally during bootups, when drm_client_modeset_probe() was waiting
>> for EDID ready event, which was delayed because IRQ handler was stuck
>> trying to deliver hotplug event.
>> Move hotplug notifications from IRQ handler to separate work to be able
>> to process IRQ events without delays.
>>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Fixes: 0cbbd5b1a012 ("drm: bridge: add support for lontium LT9611UXC bridge")
>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
>
>
> Let's wait till Monday for other comments, then I can queue the patchset.


Queued to drm-misc-fixes.

I have fixed missing parentheses in the last patch in 
lt9611uxc_hpd_work, but apparently sth went wrong and I have merged 
version without these parentheses :(, can be fixed in another future 
patchset.

Regards

Andrzej


>
>
> Regards
> Andrzej
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
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diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
index b708700e182d..fee27952ec6d 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
@@ -14,6 +14,7 @@ 
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/wait.h>
+#include <linux/workqueue.h>
 
 #include <sound/hdmi-codec.h>
 
@@ -36,6 +37,7 @@  struct lt9611uxc {
 	struct mutex ocm_lock;
 
 	struct wait_queue_head wq;
+	struct work_struct work;
 
 	struct device_node *dsi0_node;
 	struct device_node *dsi1_node;
@@ -52,6 +54,8 @@  struct lt9611uxc {
 
 	bool hpd_supported;
 	bool edid_read;
+	/* can be accessed from different threads, so protect this with ocm_lock */
+	bool hdmi_connected;
 	uint8_t fw_version;
 };
 
@@ -143,23 +147,41 @@  static irqreturn_t lt9611uxc_irq_thread_handler(int irq, void *dev_id)
 	if (irq_status)
 		regmap_write(lt9611uxc->regmap, 0xb022, 0);
 
-	lt9611uxc_unlock(lt9611uxc);
-
 	if (irq_status & BIT(0)) {
 		lt9611uxc->edid_read = !!(hpd_status & BIT(0));
 		wake_up_all(&lt9611uxc->wq);
 	}
 
 	if (irq_status & BIT(1)) {
-		if (lt9611uxc->connector.dev)
-			drm_kms_helper_hotplug_event(lt9611uxc->connector.dev);
-		else
-			drm_bridge_hpd_notify(&lt9611uxc->bridge, !!(hpd_status & BIT(1)));
+		lt9611uxc->hdmi_connected = hpd_status & BIT(1);
+		schedule_work(&lt9611uxc->work);
 	}
 
+	lt9611uxc_unlock(lt9611uxc);
+
 	return IRQ_HANDLED;
 }
 
+static void lt9611uxc_hpd_work(struct work_struct *work)
+{
+	struct lt9611uxc *lt9611uxc = container_of(work, struct lt9611uxc, work);
+	bool connected;
+
+	if (lt9611uxc->connector.dev)
+		drm_kms_helper_hotplug_event(lt9611uxc->connector.dev);
+	else {
+
+		mutex_lock(&lt9611uxc->ocm_lock);
+		connected = lt9611uxc->hdmi_connected;
+		mutex_unlock(&lt9611uxc->ocm_lock);
+
+		drm_bridge_hpd_notify(&lt9611uxc->bridge,
+				      connected ?
+				      connector_status_connected :
+				      connector_status_disconnected);
+	}
+}
+
 static void lt9611uxc_reset(struct lt9611uxc *lt9611uxc)
 {
 	gpiod_set_value_cansleep(lt9611uxc->reset_gpio, 1);
@@ -447,18 +469,21 @@  static enum drm_connector_status lt9611uxc_bridge_detect(struct drm_bridge *brid
 	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
 	unsigned int reg_val = 0;
 	int ret;
-	int connected = 1;
+	bool connected = true;
+
+	lt9611uxc_lock(lt9611uxc);
 
 	if (lt9611uxc->hpd_supported) {
-		lt9611uxc_lock(lt9611uxc);
 		ret = regmap_read(lt9611uxc->regmap, 0xb023, &reg_val);
-		lt9611uxc_unlock(lt9611uxc);
 
 		if (ret)
 			dev_err(lt9611uxc->dev, "failed to read hpd status: %d\n", ret);
 		else
 			connected  = reg_val & BIT(1);
 	}
+	lt9611uxc->hdmi_connected = connected;
+
+	lt9611uxc_unlock(lt9611uxc);
 
 	return connected ?  connector_status_connected :
 				connector_status_disconnected;
@@ -931,6 +956,8 @@  static int lt9611uxc_probe(struct i2c_client *client,
 	lt9611uxc->fw_version = ret;
 
 	init_waitqueue_head(&lt9611uxc->wq);
+	INIT_WORK(&lt9611uxc->work, lt9611uxc_hpd_work);
+
 	ret = devm_request_threaded_irq(dev, client->irq, NULL,
 					lt9611uxc_irq_thread_handler,
 					IRQF_ONESHOT, "lt9611uxc", lt9611uxc);
@@ -967,6 +994,7 @@  static int lt9611uxc_remove(struct i2c_client *client)
 	struct lt9611uxc *lt9611uxc = i2c_get_clientdata(client);
 
 	disable_irq(client->irq);
+	flush_scheduled_work();
 	lt9611uxc_audio_exit(lt9611uxc);
 	drm_bridge_remove(&lt9611uxc->bridge);