On Tue, Aug 13, 2019 at 01:02:36PM +0200, Dariusz Marcinkiewicz wrote:
> Use the new cec_notifier_conn_(un)register() functions to
> (un)register the notifier for the HDMI connector, and fill
> in the cec_connector_info.
> 
> Changes since v2:
>       - cec_notifier_phys_addr_invalidate where appropriate,
>       - don't check for NULL notifier before calling
>       cec_notifier_conn_unregister.
> Changes since v1:
>       Add memory barrier to make sure that the notifier
>       becomes visible to the irq thread once it is
>       fully constructed.
> 
> Signed-off-by: Dariusz Marcinkiewicz <dar...@google.com>
> Tested-by: Hans Verkuil <hverkuil-ci...@xs4all.nl>
> ---
>  drivers/gpu/drm/i2c/tda998x_drv.c | 33 +++++++++++++++++++++----------
>  1 file changed, 23 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c 
> b/drivers/gpu/drm/i2c/tda998x_drv.c
> index 61e042918a7fc..19a63ee1b3f53 100644
> --- a/drivers/gpu/drm/i2c/tda998x_drv.c
> +++ b/drivers/gpu/drm/i2c/tda998x_drv.c
> @@ -804,9 +804,14 @@ static irqreturn_t tda998x_irq_thread(int irq, void 
> *data)
>                       if (lvl & CEC_RXSHPDLEV_HPD) {
>                               tda998x_edid_delay_start(priv);
>                       } else {
> +                             struct cec_notifier *notify;
> +
>                               schedule_work(&priv->detect_work);
> -                             cec_notifier_set_phys_addr(priv->cec_notify,
> -                                                CEC_PHYS_ADDR_INVALID);
> +
> +                             notify = READ_ONCE(priv->cec_notify);
> +                             if (notify)
> +                                     cec_notifier_phys_addr_invalidate(
> +                                                     notify);
>                       }
>  
>                       handled = true;
> @@ -1331,6 +1336,8 @@ static int tda998x_connector_init(struct tda998x_priv 
> *priv,
>                                 struct drm_device *drm)
>  {
>       struct drm_connector *connector = &priv->connector;
> +     struct cec_connector_info conn_info;
> +     struct cec_notifier *notifier;
>       int ret;
>  
>       connector->interlace_allowed = 1;
> @@ -1347,6 +1354,19 @@ static int tda998x_connector_init(struct tda998x_priv 
> *priv,
>       if (ret)
>               return ret;
>  
> +     cec_fill_conn_info_from_drm(&conn_info, connector);
> +
> +     notifier = cec_notifier_conn_register(priv->cec_glue.parent,
> +                                           NULL, &conn_info);
> +     if (!notifier)
> +             return -ENOMEM;
> +     /*
> +      * Make sure that tda998x_irq_thread does see the notifier
> +      * when it fully constructed.
> +      */
> +     smp_wmb();
> +     priv->cec_notify = notifier;

To nitpick, this comment and the following code do not go together.

I think what you actually mean is:

         * Make sure that tda998x_irq_thread sees the notifier
         * only after it is fully constructed.

> +
>       drm_connector_attach_encoder(&priv->connector,
>                                    priv->bridge.encoder);
>  
> @@ -1790,8 +1810,7 @@ static void tda998x_destroy(struct device *dev)
>  
>       i2c_unregister_device(priv->cec);
>  
> -     if (priv->cec_notify)
> -             cec_notifier_put(priv->cec_notify);
> +     cec_notifier_conn_unregister(priv->cec_notify);

This also doesn't make sense: tda998x_destroy() is the opposite of
tda998x_create().  However, tda998x_connector_destroy() is the
opposite of tda998x_connector_create().

By moving the CEC creation code into tda998x_connector_create(), you
are creating the possibility for the following sequence to mess up
CEC and leak:

        tda998x_create()
        tda998x_connector_create()
        tda998x_connector_destroy()
        tda998x_connector_create()
        tda998x_connector_destroy()
        tda998x_destroy()

Anything you create in tda998x_connector_create() must be cleaned up
by tda998x_connector_destroy().

>  }
>  
>  static int tda998x_create(struct device *dev)
> @@ -1916,12 +1935,6 @@ static int tda998x_create(struct device *dev)
>               cec_write(priv, REG_CEC_RXSHPDINTENA, CEC_RXSHPDLEV_HPD);
>       }
>  
> -     priv->cec_notify = cec_notifier_get(dev);
> -     if (!priv->cec_notify) {
> -             ret = -ENOMEM;
> -             goto fail;
> -     }
> -
>       priv->cec_glue.parent = dev;
>       priv->cec_glue.data = priv;
>       priv->cec_glue.init = tda998x_cec_hook_init;
> -- 
> 2.23.0.rc1.153.gdeed80330f-goog
> 
> 

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