diff options
| author | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-09-14 15:17:18 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-09-14 16:02:55 +0200 |
| commit | d859a712a378a4f81c387f2afdee437a6a0a6b54 (patch) | |
| tree | 747dcae3320a02adf3151b75e02602400dff4ca1 | |
| parent | 9cf8572d6b6ffc42755f897c1623eb026cdf8c79 (diff) | |
| download | linux-d859a712a378a4f81c387f2afdee437a6a0a6b54.tar.bz2 | |
media: vidtv: adjust signal strength range
On real devices, signal strength is always a negative
number when represented in dBm. A more interesting
range is to use dBmV (which is what Kaffeine does,
for example). The conversion from the two units are
simple:
dBmV = dBm - 108
Usually, signal strength ranges up to 100dBmV. Adjust the
maximum value to be around 74 dBmV, when there's no
frequency shift, which represents a good signal.
With that, Kaffeine displays it a lot better.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
| -rw-r--r-- | drivers/media/test-drivers/vidtv/vidtv_demod.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/media/test-drivers/vidtv/vidtv_demod.c b/drivers/media/test-drivers/vidtv/vidtv_demod.c index c54c88cac84f..c825842758f0 100644 --- a/drivers/media/test-drivers/vidtv/vidtv_demod.c +++ b/drivers/media/test-drivers/vidtv/vidtv_demod.c @@ -181,12 +181,18 @@ static void vidtv_demod_update_stats(struct dvb_frontend *fe) c->block_count.stat[0].scale = scale; /* - * Add a 0.5% of randomness at the signal streangth and CNR, + * Add a 0.5% of randomness at the signal strength and CNR, * and make them different, as we want to have something closer * to a real case scenario. + * + * Also, usually, signal strength is a negative number in dBm. */ - c->strength.stat[0].svalue = state->tuner_cnr + prandom_u32_max(state->tuner_cnr / 50); - c->cnr.stat[0].svalue = state->tuner_cnr - prandom_u32_max(state->tuner_cnr / 50); + c->strength.stat[0].svalue = state->tuner_cnr; + c->strength.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50); + c->strength.stat[0].svalue -= 68000; /* Adjust to a better range */ + + c->cnr.stat[0].svalue = state->tuner_cnr; + c->cnr.stat[0].svalue -= prandom_u32_max(state->tuner_cnr / 50); } |