On Sat, Dec 29, 2018 at 11:51:16AM -0600, Brad Love wrote:
> Some software reports no signal found on a frequency due to immediately
> checking for lock as soon as set_params returns. This waits up 40ms for
> tuning operation, then from 30-150ms (dig/analog) for signal lock before
> returning from set_params and set_analog_params.
>
> Tuning typically completes in 20-30ms. Digital tuning will additionally
> wait depending on signal characteristics. Analog tuning will wait the
> full timeout in case of no signal.
This looks like a workaround for broken userspace. Very possibly this
is software was tested on a different frontend which does wait for tuning
to complete.
This is a change in uapi and will have to be done for all frontends, and
documented. However I doubt such a change is acceptable.
What software are you refering to?
Sean
>
> Signed-off-by: Brad Love <b...@nextdimension.cc>
> ---
> drivers/media/tuners/si2157.c | 87
> +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 87 insertions(+)
>
> diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c
> index ff462ba..1737007 100644
> --- a/drivers/media/tuners/si2157.c
> +++ b/drivers/media/tuners/si2157.c
> @@ -318,6 +318,89 @@ static int si2157_sleep(struct dvb_frontend *fe)
> return ret;
> }
>
> +static int si2157_tune_wait(struct i2c_client *client, u8 is_digital)
> +{
> +#define TUN_TIMEOUT 40
> +#define DIG_TIMEOUT 30
> +#define ANALOG_TIMEOUT 150
> + struct si2157_dev *dev = i2c_get_clientdata(client);
> + int ret;
> + unsigned long timeout;
> + unsigned long start_time;
> + u8 wait_status;
> + u8 tune_lock_mask;
> +
> + if (is_digital)
> + tune_lock_mask = 0x04;
> + else
> + tune_lock_mask = 0x02;
> +
> + mutex_lock(&dev->i2c_mutex);
> +
> + /* wait tuner command complete */
> + start_time = jiffies;
> + timeout = start_time + msecs_to_jiffies(TUN_TIMEOUT);
> + while (!time_after(jiffies, timeout)) {
> + ret = i2c_master_recv(client, &wait_status,
> + sizeof(wait_status));
> + if (ret < 0) {
> + goto err_mutex_unlock;
> + } else if (ret != sizeof(wait_status)) {
> + ret = -EREMOTEIO;
> + goto err_mutex_unlock;
> + }
> +
> + /* tuner done? */
> + if ((wait_status & 0x81) == 0x81)
> + break;
> + usleep_range(5000, 10000);
> + }
> +
> + dev_dbg(&client->dev, "tuning took %d ms, status=0x%x\n",
> + jiffies_to_msecs(jiffies) - jiffies_to_msecs(start_time),
> + wait_status);
> +
> + /* if we tuned ok, wait a bit for tuner lock */
> + if ((wait_status & 0x81) == 0x81) {
> + if (is_digital)
> + timeout = jiffies + msecs_to_jiffies(DIG_TIMEOUT);
> + else
> + timeout = jiffies + msecs_to_jiffies(ANALOG_TIMEOUT);
> + while (!time_after(jiffies, timeout)) {
> + ret = i2c_master_recv(client, &wait_status,
> + sizeof(wait_status));
> + if (ret < 0) {
> + goto err_mutex_unlock;
> + } else if (ret != sizeof(wait_status)) {
> + ret = -EREMOTEIO;
> + goto err_mutex_unlock;
> + }
> +
> + /* tuner locked? */
> + if (wait_status & tune_lock_mask)
> + break;
> + usleep_range(5000, 10000);
> + }
> + }
> +
> + dev_dbg(&client->dev, "tuning+lock took %d ms, status=0x%x\n",
> + jiffies_to_msecs(jiffies) - jiffies_to_msecs(start_time),
> + wait_status);
> +
> + if ((wait_status & 0xc0) != 0x80) {
> + ret = -ETIMEDOUT;
> + goto err_mutex_unlock;
> + }
> +
> + mutex_unlock(&dev->i2c_mutex);
> + return 0;
> +
> +err_mutex_unlock:
> + mutex_unlock(&dev->i2c_mutex);
> + dev_dbg(&client->dev, "failed=%d\n", ret);
> + return ret;
> +}
> +
> static int si2157_set_params(struct dvb_frontend *fe)
> {
> struct i2c_client *client = fe->tuner_priv;
> @@ -417,6 +500,8 @@ static int si2157_set_params(struct dvb_frontend *fe)
> dev->bandwidth = bandwidth;
> dev->frequency = c->frequency;
>
> + si2157_tune_wait(client, 1); /* wait to complete, ignore any errors */
> +
> return 0;
> err:
> dev->bandwidth = 0;
> @@ -626,6 +711,8 @@ static int si2157_set_analog_params(struct dvb_frontend
> *fe,
> #endif
> dev->bandwidth = bandwidth;
>
> + si2157_tune_wait(client, 0); /* wait to complete, ignore any errors */
> +
> return 0;
> err:
> dev->bandwidth = 0;
> --
> 2.7.4
