Hi Andrzej,

On Mon, Aug 27, 2018 at 06:15:59PM +0200, Andrzej Hajda wrote:

On 30.07.2018 18:42, Russell King wrote:

quoted

 static void tda998x_destroy(struct tda998x_priv *priv)
 {
+	drm_bridge_remove(&priv->bridge);
+
 	/* disable all IRQs and free the IRQ handler */
 	cec_write(priv, REG_CEC_RXSHPDINTENA, 0);
 	reg_clear(priv, REG_INT_FLAGS_2, INT_FLAGS_2_EDID_BLK_RD);

@@ -1650,6 +1663,7 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
 	mutex_init(&priv->mutex);	/* protect the page access */
 	mutex_init(&priv->audio_mutex); /* protect access from audio thread */
 	mutex_init(&priv->edid_mutex);
+	INIT_LIST_HEAD(&priv->bridge.list);

This line can be probably removed, unless there is a reason I am not
aware of.

The addition above of drm_bridge_remove() to tda998x_destroy() means
that we end up calling this function in the error cleanup path.  This
avoids unnecessary complexity with lots of different gotos - tda998x
has had a long history of not cleaning up stuff properly.

devm interfaces for bridge do not help avoid that - devm stuff only
works if everything that is registered previously is cleaned up via
devm mechanisms to ensure that a device's interface becomes unavailable
before stuff (eg, edid timers, detect work) is started to be cleaned up.
Otherwise, there's a chance of this stuff being triggered during
tear-down.

quoted

+static int tda998x_bind(struct device *dev, struct device *master, void *data)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct drm_device *drm = data;
+	struct tda998x_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, priv);
+
+	ret = tda998x_create(client, priv);
+	if (ret)
+		return ret;
+
+	ret = tda998x_encoder_init(dev, drm);
+	if (ret) {
+		tda998x_destroy(priv);
+		return ret;
+	}
+	return 0;

It could be replaced by:
??? ret = tda998x_encoder_init(dev, drm);
??? if (ret)
??? ??? tda998x_destroy(priv);
??? return ret;

but this is probably matter of taste.

It's not clear to me what "It" is - I think you're suggesting combining
tda998x_create() and tda998x_encoder_init() ?

The code is structured this way to make the following patches easier -
there is no point of combining things only to have to then break them
apart again in a later patch.  Please see patch 7, where tda998x_create()
moves out of this function, where exactly this happens.

Moreover I guess priv->is_on could be removed if enable/disable
callbacks are called only by drm_core, but this is for another patch.

Is it guaranteed that a bridge ->enable or ->disable callback won't be
called twice, even for legacy drivers?  I think atomic guarantees this
but I don't think it's guaranteed for legacy drivers.

I'm guessing Rob had a reason why he added the check when he originally
created the driver (encoder ->dpms can be called for the same dpms
state multiple times?)

-- 
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