[linux-dvb] Re: Time till channel has lock

[Martin Neuditschko <yosuke.tomoe@gmx.net>]

On Fri, Oct 11, 2002 at 08:49:39PM +0200, Andreas Poethke wrote:
> On Wednesday 09 October 2002 20:25, Martin Neuditschko wrote:
> > Hi!
> >
> > I am using a Hauppauge DVB-c Cable-Card,
> > kernel-2.4.18,
> > Newstruct driver snapshot from today (09.10.02)
> > UPC-Telekabel-Austria -> QAM_256
> >
> > If I start "./czap RTL2" sometimes it only uses about 5 seconds
> > to lock the channel, but sometimes it uses up to 2 minutes.
> > I have tested this one channel only (RTL2).
> > I mean I started "czap RTL2", waited till channel is locked,
> > killed czap and started "czap RTL2" again without switching to
> > any other channel.
> >
> > If I use the newstruct driver snapshot from 08.09.02 it is much
> > faster. Some ideas about the problem?
> 
> please try to change file DVB/driver/frontend/alps_bsrv2.c at line 134
> from
> 
>  u8 buf [4] = { (div >> 8) & 0x7f, div & 0xff, 0x95, (pwr << 5) | 0x30 };
> 
> to
> 
>  u8 buf [4] = { (div >> 8) & 0x7f, div & 0xff, 0x95, (pwr << 6) | 0x30 };
> 
> and report if this fixes the problem. (this works quite well with my card.)

I tested it now, but it does not solve the problem for me. I think
that something is not reset cleanly if a channel is tuned and I think
that this possibly could only be observed with a DVB-c card (and /
or QAM_256).

Because of the 'not reset cleanly' take a look at following
two tests.
First './czap RTL2' was done immediately after loading the drivers. 
Here the bit error rate is at the beginning 000fffff.
Then I have done a <Ctrl>+C and again: './czap RTL2'. Here the
bit error rate is not anymore 000fffff. It is the same one as
before killing the first czap.

I don' t know if this is not OK, but for me it seems strange.

melchior:/usr/local/src/devel/newstruct_021013/apps/szap # ./czap RTL2
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 378000000 Hz
status 07 | signal 8787 | snr d9d9 | ber 000fffff | unc 0000007f |
status 07 | signal 8989 | snr dada | ber 000fffff | unc 0000007f |
status 07 | signal 8787 | snr d8d8 | ber 000fffff | unc 0000007f |
status 07 | signal 8787 | snr d8d8 | ber 000fffff | unc 0000007f |
status 07 | signal 8787 | snr dbdb | ber 000fffff | unc 0000007f |
status 07 | signal 8787 | snr dbdb | ber 000fffff | unc 0000007f |
status 1f | signal e3e3 | snr eded | ber 000fffff | unc 0000007f | FE_HAS_LOCK
status 1f | signal ffff | snr eded | ber 000fffff | unc 00000000 | FE_HAS_LOCK
status 1f | signal ffff | snr eded | ber 00032d66 | unc 00000000 | FE_HAS_LOCK
status 1f | signal ffff | snr eded | ber 00032d66 | unc 00000000 | FE_HAS_LOCK
status 1f | signal ffff | snr eded | ber 0000aa0a | unc 00000000 | FE_HAS_LOCK
status 1f | signal ffff | snr eeee | ber 0000aa65 | unc 00000000 | FE_HAS_LOCK

melchior:/usr/local/src/devel/newstruct_021013/apps/szap # ./czap RTL2
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 378000000 Hz
status 07 | signal 8888 | snr d8d8 | ber 0000ab92 | unc 0000007f |
status 00 | signal 8b8b | snr d7d7 | ber 0000ab92 | unc 0000007f |
status 07 | signal 8787 | snr d9d9 | ber 0000ab92 | unc 0000007f |
status 07 | signal 8787 | snr d8d8 | ber 0000ab92 | unc 0000007f |
status 07 | signal 8787 | snr d8d8 | ber 0000ab92 | unc 0000007f |
status 07 | signal 8787 | snr dbdb | ber 0000ab92 | unc 0000007f |
status 07 | signal 8787 | snr d8d8 | ber 0000ab92 | unc 0000007f |


best regards
Martin Neuditschko


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