On Wed, 2011-07-06 at 21:35 +0100, Malcolm Priestley wrote:
> On Wed, 2011-07-06 at 13:34 +0200, Sébastien RAILLARD (COEXSI) wrote:
> >
> > > -----Original Message-----
> > > From: Oliver Endriss [mailto:o.endr...@gmx.de]
> > > Sent: lundi 4 juillet 2011 00:43
> > > To: Linux Media Mailing List
> > > Cc: Sébastien RAILLARD (COEXSI); Malcolm Priestley
> > > Subject: Re: [DVB] TT S-1500b tuning issue
> > >
> > > On Wednesday 29 June 2011 15:16:10 Sébastien RAILLARD wrote:
> > > > Dear all,
> > > >
> > > > We have found what seems to be a tuning issue in the driver for the
> > > > ALPS BSBE1-D01A used in the new TT-S-1500b card from Technotrend.
> > > > On some transponders, like ASTRA 19.2E 11817-V-27500, the card can
> > > > work very well (no lock issues) for hours.
> > > >
> > > > On some other transponders, like ASTRA 19.2E 11567-V-22000, the card
> > > > nearly never manage to get the lock: it's looking like the signal
> > > > isn't good enough.
> > >
> > > Afaics the problem is caused by the tuning loop
> > > for (tm = -6; tm < 7;)
> > > in stv0288_set_frontend().
> > >
> > > I doubt that this code works reliably.
> > > Apparently it never obtains a lock within the given delay (30us).
> It's actually quite slow caused by any delay in the I2C bus. I doubt
> given the age many controllers run at the 400kHz spec, if barely 100kHz.
>
> > >
> > > Could you please try the attached patch?
> > > It disables the loop and tries to tune to the center frequency.
> > >
> >
> > Ok, I've tested this patch with ASTRA 19.2 #24 transponder that wasn't
> > always working: it seems to work.
> > I think it would be great to test it for few days more to be sure.
>
> Unfortunately, this patch does not work well at all.
>
> All that is happening is that the carrier offset is getting forced to 0,
> after it has been updated by the lock control register losing a 'good'
> lock.
>
> The value is typically around ~f800+.
>
> Perhaps the loop should be knocked down slightly to -9. The loop was
> probably intended for 22000 symbol rate.
The following patch provides wider carrier search.
As with existing code search starts at MSB aligned. The boundary
is widened to start at -9. In order to save time, if no carrier is
detected at the start it advances to the next alignment until carrier
is found.
The stv0288 will detect a DVB-S2 carrier on all steps , a
time out of 11 steps is introduced to drop out of the loop.
In stv0288_set_symbol carrier and timing loops are restored to
default values (inittab) before setting the symbol rate on each tune. A
slight drift was noticed with full scan in the higher IF frequencies of
each band.
Signed-off-by: Malcolm Priestley <tvbox...@gmail.com>
---
drivers/media/dvb/frontends/stv0288.c | 29
+++++++++++++++++++++--------
1 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/drivers/media/dvb/frontends/stv0288.c
b/drivers/media/dvb/frontends/stv0288.c
index 8e0cfad..0aa3962 100644
--- a/drivers/media/dvb/frontends/stv0288.c
+++ b/drivers/media/dvb/frontends/stv0288.c
@@ -127,6 +127,11 @@ static int stv0288_set_symbolrate(struct
dvb_frontend *fe, u32 srate)
if ((srate < 1000000) || (srate > 45000000))
return -EINVAL;
+ stv0288_writeregI(state, 0x22, 0);
+ stv0288_writeregI(state, 0x23, 0);
+ stv0288_writeregI(state, 0x2b, 0xff);
+ stv0288_writeregI(state, 0x2c, 0xf7);
+
temp = (unsigned int)srate / 1000;
temp = temp * 32768;
@@ -461,6 +466,7 @@ static int stv0288_set_frontend(struct dvb_frontend
*fe,
char tm;
unsigned char tda[3];
+ u8 reg, time_out = 0;
dprintk("%s : FE_SET_FRONTEND\n", __func__);
@@ -488,22 +494,29 @@ static int stv0288_set_frontend(struct
dvb_frontend *fe,
/* Carrier lock control register */
stv0288_writeregI(state, 0x15, 0xc5);
- tda[0] = 0x2b; /* CFRM */
tda[2] = 0x0; /* CFRL */
- for (tm = -6; tm < 7;) {
+ for (tm = -9; tm < 7;) {
/* Viterbi status */
- if (stv0288_readreg(state, 0x24) & 0x8)
- break;
-
- tda[2] += 40;
- if (tda[2] < 40)
+ reg = stv0288_readreg(state, 0x24);
+ if (reg & 0x8)
+ break;
+ if (reg & 0x80) {
+ time_out++;
+ if (time_out > 10)
+ break;
+ tda[2] += 40;
+ if (tda[2] < 40)
+ tm++;
+ } else {
tm++;
+ tda[2] = 0;
+ time_out = 0;
+ }
tda[1] = (unsigned char)tm;
stv0288_writeregI(state, 0x2b, tda[1]);
stv0288_writeregI(state, 0x2c, tda[2]);
udelay(30);
}
-
state->tuner_frequency = c->frequency;
state->fec_inner = FEC_AUTO;
state->symbol_rate = c->symbol_rate;
--
1.7.4.1
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