diff options
| author | Klaus Schmidinger <Klaus.Schmidinger@tvdr.de> | 2012-06-02 18:04:17 +0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-06-19 02:29:59 +0400 |
| commit | fdaaee6c4a63e364b7f9c8bfdb218e6aaa65f1cf (patch) | |
| tree | 97f0056131eed4460cb946ac36a225703b2d64ea | |
| parent | 4a62817095696b9831721485bb5c607eba86633f (diff) | |
| download | linux-fdaaee6c4a63e364b7f9c8bfdb218e6aaa65f1cf.tar.xz | |
[media] DVB: stb0899: speed up getting BER values
stb0899_read_ber() takes 500ms (half a second!) to deliver the current
BER value. Apparently it takes 5 subsequent readings, with a 100ms pause
between them (and even before the first one). This is a real performance
brake if an application freqeuently reads the BER of several devices.
The attached patch reduces this to a single reading, with no more pausing.
I didn't observe any negative side effects of this change.
Signed-off-by: Klaus Schmidinger <Klaus.Schmidinger@tvdr.de>
Cc: Manu Abraham <abraham.manu@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
| -rw-r--r-- | drivers/media/dvb/frontends/stb0899_drv.c | 22 |
1 files changed, 6 insertions, 16 deletions
diff --git a/drivers/media/dvb/frontends/stb0899_drv.c b/drivers/media/dvb/frontends/stb0899_drv.c index 8b0dc74a3298..5d7f8a9b451b 100644 --- a/drivers/media/dvb/frontends/stb0899_drv.c +++ b/drivers/media/dvb/frontends/stb0899_drv.c @@ -1129,7 +1129,6 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber) struct stb0899_internal *internal = &state->internal; u8 lsb, msb; - u32 i; *ber = 0; @@ -1137,14 +1136,9 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber) case SYS_DVBS: case SYS_DSS: if (internal->lock) { - /* average 5 BER values */ - for (i = 0; i < 5; i++) { - msleep(100); - lsb = stb0899_read_reg(state, STB0899_ECNT1L); - msb = stb0899_read_reg(state, STB0899_ECNT1M); - *ber += MAKEWORD16(msb, lsb); - } - *ber /= 5; + lsb = stb0899_read_reg(state, STB0899_ECNT1L); + msb = stb0899_read_reg(state, STB0899_ECNT1M); + *ber = MAKEWORD16(msb, lsb); /* Viterbi Check */ if (STB0899_GETFIELD(VSTATUS_PRFVIT, internal->v_status)) { /* Error Rate */ @@ -1157,13 +1151,9 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber) break; case SYS_DVBS2: if (internal->lock) { - /* Average 5 PER values */ - for (i = 0; i < 5; i++) { - msleep(100); - lsb = stb0899_read_reg(state, STB0899_ECNT1L); - msb = stb0899_read_reg(state, STB0899_ECNT1M); - *ber += MAKEWORD16(msb, lsb); - } + lsb = stb0899_read_reg(state, STB0899_ECNT1L); + msb = stb0899_read_reg(state, STB0899_ECNT1M); + *ber = MAKEWORD16(msb, lsb); /* ber = ber * 10 ^ 7 */ *ber *= 10000000; *ber /= (-1 + (1 << (4 + 2 * STB0899_GETFIELD(NOE, internal->err_ctrl)))); |