As reported at: https://tvheadend.org/issues/5625
Retrieving certain status can cause discontinuity issues.
Prevent that by adding a timeout to each status logic.
Currently, the timeout is estimated based at the channel bandwidth. There are other parameters that may also affect the timeout, but that would require a per-delivery system calculus and probably more information about how cxd2481er works, with we don't have.
So, do a poor man's best guess.
Cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org --- drivers/media/dvb-frontends/cxd2841er.c | 59 +++++++++++++++++++++++++ 1 file changed, 59 insertions(+)
diff --git a/drivers/media/dvb-frontends/cxd2841er.c b/drivers/media/dvb-frontends/cxd2841er.c index 1b30cf570803..71428b0d2620 100644 --- a/drivers/media/dvb-frontends/cxd2841er.c +++ b/drivers/media/dvb-frontends/cxd2841er.c @@ -60,6 +60,13 @@ struct cxd2841er_priv { enum cxd2841er_xtal xtal; enum fe_caps caps; u32 flags; + + unsigned long ber_interval; + unsigned long ucb_interval; + + unsigned long ber_time; + unsigned long ucb_time; + unsigned long snr_time; };
static const struct cxd2841er_cnr_data s_cn_data[] = { @@ -1941,12 +1948,20 @@ static void cxd2841er_read_ber(struct dvb_frontend *fe) struct cxd2841er_priv *priv = fe->demodulator_priv; u32 ret, bit_error = 0, bit_count = 0;
+ if (priv->ber_time && + (!time_after(jiffies, priv->ber_time))) + return; + dev_dbg(&priv->i2c->dev, "%s()\n", __func__); switch (p->delivery_system) { case SYS_DVBC_ANNEX_A: case SYS_DVBC_ANNEX_B: case SYS_DVBC_ANNEX_C: ret = cxd2841er_read_ber_c(priv, &bit_error, &bit_count); + + if (!priv->ber_interval && p->symbol_rate) + priv->ber_interval = (10000000) / (p->symbol_rate / 1000); + break; case SYS_ISDBT: ret = cxd2841er_read_ber_i(priv, &bit_error, &bit_count); @@ -1978,6 +1993,18 @@ static void cxd2841er_read_ber(struct dvb_frontend *fe) p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE; p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE; } + + /* + * If the per-delivery system doesn't specify, set a default timeout + * that will wait for ~12.5 seconds for 8MHz channels + */ + if (!priv->ber_interval && p->bandwidth_hz) + priv->ber_interval = (100000000) / (p->bandwidth_hz / 1000); + + if (priv->ber_interval < 1000) + priv->ber_interval = 1000; + + priv->ber_time = jiffies + msecs_to_jiffies(priv->ber_interval); }
static void cxd2841er_read_signal_strength(struct dvb_frontend *fe) @@ -2037,6 +2064,13 @@ static void cxd2841er_read_snr(struct dvb_frontend *fe) struct dtv_frontend_properties *p = &fe->dtv_property_cache; struct cxd2841er_priv *priv = fe->demodulator_priv;
+ if (priv->snr_time && + (!time_after(jiffies, priv->snr_time))) + return; + + /* Preventing asking SNR more than once per second */ + priv->snr_time = jiffies + msecs_to_jiffies(1000); + dev_dbg(&priv->i2c->dev, "%s()\n", __func__); switch (p->delivery_system) { case SYS_DVBC_ANNEX_A: @@ -2081,12 +2115,18 @@ static void cxd2841er_read_ucblocks(struct dvb_frontend *fe) struct cxd2841er_priv *priv = fe->demodulator_priv; u32 ucblocks = 0;
+ if (priv->ucb_time && + (!time_after(jiffies, priv->ucb_time))) + return; + dev_dbg(&priv->i2c->dev, "%s()\n", __func__); switch (p->delivery_system) { case SYS_DVBC_ANNEX_A: case SYS_DVBC_ANNEX_B: case SYS_DVBC_ANNEX_C: cxd2841er_read_packet_errors_c(priv, &ucblocks); + if (!priv->ucb_interval && p->symbol_rate) + priv->ucb_interval = (100 * 204 * 1000 * 8) / p->symbol_rate; break; case SYS_DVBT: cxd2841er_read_packet_errors_t(priv, &ucblocks); @@ -2105,6 +2145,18 @@ static void cxd2841er_read_ucblocks(struct dvb_frontend *fe)
p->block_error.stat[0].scale = FE_SCALE_COUNTER; p->block_error.stat[0].uvalue = ucblocks; + + /* + * If the per-delivery system doesn't specify, set a default timeout + * that will wait 20-30 seconds + */ + if (!priv->ucb_interval && p->bandwidth_hz) + priv->ucb_interval = (100 * 204 * 1000 * 8) / p->bandwidth_hz; + + if (priv->ucb_interval < 1000) + priv->ucb_interval = 1000; + + priv->ucb_time = jiffies + msecs_to_jiffies(priv->ucb_interval); }
static int cxd2841er_dvbt2_set_profile( @@ -3360,6 +3412,13 @@ static int cxd2841er_set_frontend_s(struct dvb_frontend *fe) p->post_bit_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE; p->post_bit_count.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+ /* Reset the wait for jiffies logic */ + priv->ber_interval = 0; + priv->ucb_interval = 0; + priv->ber_time = 0; + priv->ucb_time = 0; + priv->snr_time = 0; + return ret; }