[linux-dvb] Re: Tuning problems with the refactored drivers

[lamikr <lamikr@cc.jyu.fi>]

Andrew de Quincey wrote:

> > First it tuned pretty badly. (Only 30 channels or so found) but after
> > that I added the mdelay(200)
> > command to line 116 of ves1820.c method ves1820_setup_reg0 and it
> > started to tune channels very well.
> > Now it can even find channels from out national tv channel! So maybe the
> > mdelay-line should also be added in the
> > CVS? (mdelay(50) got removed when you removed that hack)
> >
> >    ves1820_writereg(state, 0x00, reg0 & 0xfe);
> >    ves1820_writereg(state, 0x00, reg0 | 0x01);
> >    mdelay(200);                                                      //
> > this is the new line!
> >    
> Does setting the dvb_override_tune_delay parameter to 200 have the same effect 
> as doing this? Its just that there is a mechanism defined for solving exactly 
> this problem which I would prefer to use rather than putting an mdelay in the 
> frontend itself.
>
> Glad to hear its getting better!
>  
How can I test this? Should I change in /build-2.6/insmod.sh

   insmod ./ves1820.ko
to
   insmod ./ves1820.ko dvb_override_tune_delay=200
?

> > Is this ms line btw. CPU speed dependent. (Would slow PC's require
> > longer delay and faster one shorter?)
> >    
> It shouldn't do - the demod has its own clock.
>  
I am just trying to understand a little bit bigger picture where this is 
delay is actually affecting on.
Will this delay somehow cause tune function from usermode to block a 
little bit longer so that the demod hardware
has a little bit more time to really find channels from the stream?

Btw. even I can now tune all channels ok, I have still problems to get 
some of the channels locked. (these from the 162 mhz)
(Some others locks very fastly)

[lamikr@aragorn szap]$ ./czap "YLE TV1"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file '/home/lamikr/.czap/channels.conf'
19 YLE TV1:162000000:INVERSION_AUTO:6900000:FEC_NONE:QAM_128:512:650:17
19 YLE TV1: f 162000000, s 6900000, i 2, fec 0, qam 4, v 0x200, a 0x28a
status 00 | signal 8b8b | snr aaaa | ber 00029220 | unc ffffffff |
status 07 | signal d5d5 | snr dfdf | ber 00029220 | unc ffffffff |
status 00 | signal d6d6 | snr c3c3 | ber 00029220 | unc ffffffff |
status 1f | signal ffff | snr e9e9 | ber 00029220 | unc ffffffff | 
FE_HAS_LOCK
status 00 | signal f8f8 | snr c3c3 | ber 00029220 | unc ffffffff |
status 1f | signal ffff | snr e7e7 | ber 00029220 | unc ffffffff | 
FE_HAS_LOCK
status 00 | signal dbdb | snr c5c5 | ber 00029220 | unc ffffffff |
status 00 | signal d5d5 | snr c6c6 | ber 00029220 | unc ffffffff |
status 1f | signal d7d7 | snr d9d9 | ber 00029220 | unc ffffffff | 
FE_HAS_LOCK
status 00 | signal d6d6 | snr c4c4 | ber 00029220 | unc ffffffff |
status 00 | signal d7d7 | snr c6c6 | ber 00029220 | unc ffffffff |
status 00 | signal d4d4 | snr c4c4 | ber 00029220 | unc ffffffff |
status 00 | signal d4d4 | snr c8c8 | ber 00029220 | unc ffffffff |
status 00 | signal d7d7 | snr c3c3 | ber 00029220 | unc ffffffff |
status 00 | signal d4d4 | snr c3c3 | ber 00029220 | unc ffffffff |
status 00 | signal d6d6 | snr c3c3 | ber 00029220 | unc ffffffff |
status 1f | signal d5d5 | snr e0e0 | ber 00029220 | unc ffffffff | 
FE_HAS_LOCK
status 00 | signal d7d7 | snr c3c3 | ber 00029220 | unc ffffffff |
status 00 | signal d6d6 | snr c6c6 | ber 00029220 | unc ffffffff |
status 00 | signal d6d6 | snr c3c3 | ber 00029220 | unc ffffffff |
status 1f | signal ffff | snr e9e9 | ber 00029220 | unc ffffffff | 
FE_HAS_LOCK

Mika