On Tue, Jan 6, 2015 at 2:08 PM, Mauro Carvalho Chehab
<mchehab@xxxxxxxxxxxxxxx> wrote:
> If the dvb frontend thread starts, the tuner should be switched
> to the frontend. Add a code that ensures that this will happen,
> using the media controller.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
>
> diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
> index c2c559105f64..04e949ad9722 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -590,12 +590,99 @@ static void dvb_frontend_wakeup(struct dvb_frontend *fe)
> wake_up_interruptible(&fepriv->wait_queue);
> }
>
> +/**
> + * dvb_enable_media_tuner() - tries to enable the DVB tuner
> + *
> + * @fe: struct dvb_frontend pointer
> + *
> + * This function ensures that just one media tuner is enabled for a given
> + * frontend. It has two different behaviors:
> + * - For trivial devices with just one tuner:
> + * it just enables the existing tuner->fe link
> + * - For devices with more than one tuner:
> + * It is up to the driver to implement the logic that will enable one tuner
> + * and disable the other ones. However, if more than one tuner is enabled for
> + * the same frontend, it will print an error message and return -EINVAL.
> + *
> + * At return, it will return the error code returned by media_entity_setup_link,
> + * or 0 if everything is OK, if no tuner is linked to the frontend or if the
> + * mdev is NULL.
> + */
> +static int dvb_enable_media_tuner(struct dvb_frontend *fe)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> + struct dvb_frontend_private *fepriv = fe->frontend_priv;
> + struct dvb_adapter *adapter = fe->dvb;
> + struct media_device *mdev = adapter->mdev;
> + struct media_entity *entity, *source;
> + struct media_link *link, *found_link = NULL;
> + int i, ret, n_links = 0, active_links = 0;
> +
> + if (!mdev)
> + return 0;
> +
> + entity = fepriv->dvbdev->entity;
> + for (i = 0; i < entity->num_links; i++) {
> + link = &entity->links[i];
> + if (link->sink->entity == entity) {
> + found_link = link;
> + n_links++;
> + if (link->flags & MEDIA_LNK_FL_ENABLED)
> + active_links++;
> + }
> + }
Does this code path need to be protected with a mutex?
> +
> + if (!n_links || active_links == 1 || !found_link)
> + return 0;
> +
> + /*
> + * If a frontend has more than one tuner linked, it is up to the driver
> + * to select with one will be the active one, as the frontend core can't
> + * guess. If the driver doesn't do that, it is a bug.
> + */
> + if (n_links > 1 && active_links != 1) {
> + dev_err(fe->dvb->device,
> + "WARNING: there are %d active links among %d tuners. This is a driver's bug!\n",
> + active_links, n_links);
> + return -EINVAL;
> + }
> +
> + source = found_link->source->entity;
> + for (i = 0; i < source->num_links; i++) {
> + struct media_entity *sink;
> + int flags = 0;
> +
> + link = &source->links[i];
> + sink = link->sink->entity;
> +
> + if (sink == entity)
> + flags = MEDIA_LNK_FL_ENABLED;
> +
> + ret = media_entity_setup_link(link, flags);
> + if (ret) {
> + dev_err(fe->dvb->device,
> + "Couldn't change link %s->%s to %s. Error %d\n",
> + source->name, sink->name,
> + flags ? "enabled" : "disabled",
> + ret);
> + return ret;
> + } else
> + dev_dbg(fe->dvb->device,
> + "link %s->%s was %s\n",
> + source->name, sink->name,
> + flags ? "ENABLED" : "disabled");
> + }
> +#endif
> + return 0;
> +}
> +
> static int dvb_frontend_thread(void *data)
> {
> struct dvb_frontend *fe = data;
> struct dvb_frontend_private *fepriv = fe->frontend_priv;
> fe_status_t s;
> enum dvbfe_algo algo;
> + int ret;
>
> bool re_tune = false;
> bool semheld = false;
> @@ -609,6 +696,13 @@ static int dvb_frontend_thread(void *data)
> fepriv->wakeup = 0;
> fepriv->reinitialise = 0;
>
> + ret = dvb_enable_media_tuner(fe);
> + if (ret) {
> + /* FIXME: return an error if it fails */
> + dev_info(fe->dvb->device,
> + "proceeding with FE task\n");
> + }
> +
> dvb_frontend_init(fe);
>
> set_freezable();
> --
> 2.1.0
>
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