[linux-dvb] TechnoTrend C-1501 - Locking issues on 388Mhz

klaas de waal klaas.de.waal at gmail.com
Thu Oct 9 22:15:30 CEST 2008


Hi Jeremy,

I have the Technotrend C-1501 now locking at 388MHz.
The table tda827xa_dvbt contains the settings for each frequency segment.
The frequency values (first column) are for  the frequency plus the IF, so
for 388MHz
this is 388+5 gives 393 MHz. The table starts a new segment at 390MHz, it
then
starts to use VCO2 instead of VCO1.
I have now (hack, hack) changed the segment start from 390 to 395MHz so
that the 388MHz is still tuned with VCO1, and this works OK!!
Like this:

static const struct tda827xa_data tda827xa_dvbt[] = {
    { .lomax =  56875000, .svco = 3, .spd = 4, .scr = 0, .sbs = 0, .gc3 =
1},
    { .lomax =  67250000, .svco = 0, .spd = 3, .scr = 0, .sbs = 0, .gc3 =
1},
    { .lomax =  81250000, .svco = 1, .spd = 3, .scr = 0, .sbs = 0, .gc3 =
1},
    { .lomax =  97500000, .svco = 2, .spd = 3, .scr = 0, .sbs = 0, .gc3 =
1},
    { .lomax = 113750000, .svco = 3, .spd = 3, .scr = 0, .sbs = 1, .gc3 =
1},
    { .lomax = 134500000, .svco = 0, .spd = 2, .scr = 0, .sbs = 1, .gc3 =
1},
    { .lomax = 154000000, .svco = 1, .spd = 2, .scr = 0, .sbs = 1, .gc3 =
1},
    { .lomax = 162500000, .svco = 1, .spd = 2, .scr = 0, .sbs = 1, .gc3 =
1},
    { .lomax = 183000000, .svco = 2, .spd = 2, .scr = 0, .sbs = 1, .gc3 =
1},
    { .lomax = 195000000, .svco = 2, .spd = 2, .scr = 0, .sbs = 2, .gc3 =
1},
    { .lomax = 227500000, .svco = 3, .spd = 2, .scr = 0, .sbs = 2, .gc3 =
1},
    { .lomax = 269000000, .svco = 0, .spd = 1, .scr = 0, .sbs = 2, .gc3 =
1},
    { .lomax = 290000000, .svco = 1, .spd = 1, .scr = 0, .sbs = 2, .gc3 =
1},
    { .lomax = 325000000, .svco = 1, .spd = 1, .scr = 0, .sbs = 3, .gc3 =
1},
#ifdef ORIGINAL // KdW test
    { .lomax = 390000000, .svco = 2, .spd = 1, .scr = 0, .sbs = 3, .gc3 =
1},
#else
    { .lomax = 395000000, .svco = 2, .spd = 1, .scr = 0, .sbs = 3, .gc3 =
1},
#endif
    { .lomax = 455000000, .svco = 3, .spd = 1, .scr = 0, .sbs = 3, .gc3 =
1},
etc etc

I plan to do a test on the all frequencies in the near future, at
least on all the Dutch Ziggo frequencies.
Because I cannot test what will happen if the driver is used for DVB-T (what
the name of the table suggests) it might be best to make a separate
tda827xa_dvbc table.

About the timeout messages, they come from the SAA7134 and they happen
fairly random. I have looked at debug traces and everytime it happens it
does a retry and then succeeds, so I think this can be ignored for the time
being.
Maybe you can check if the fix/hack also works for you?
If there is an official maintainer of this driver, maybe he can comment?

Groetjes,
Klaas



On Tue, Sep 30, 2008 at 11:18 AM, <jerremy at wordtgek.nl> wrote:

> Hi Klaas,
>
> Perhaps its an idea to post this on the linux-dvb mailing list, if anything
> it keeps the subject alive.
>
> I've spent an hour or so playing with several of the parameters of the
> demodulator (the tda10023), mostly because this was suggest in one of the
> older posts about this issue. However none of my efforts gave any desired
> result and quickly got tired of unloading / reloading my drivers (which
> every so often required a hard reset as well).
>
> But if you find anything, that would be great ;)
>
> Gr. Jerremy
>
> On Mon, 29 Sep 2008 11:35:03 +0200, "klaas de waal"
> <klaas.de.waal at gmail.com> wrote:
> > Hallo Jeremy,
> > I have exactly the same problem with my C-1501 card: tuning problems on
> > 388
> > MHz but OK on most other frequencies.
> > It works OK with WIndowsXP on all frequencies including the 388MHz, so
> the
> > hardware is OK and it must be a software issue.
> > I have over the weekend put in a lot of printk for debugging but have not
> > found it yet.
> > I will keep you updated.
> >
> > Groetjes,
> > Klaas
> >
> >
> > On Thu, Sep 11, 2008 at 5:50 PM, <jerremy at wordtgek.nl> wrote:
> >
> >> Hi,
> >>
> >> This issue has come up at least once a bit more then a month ago and is
> >> still present in the current release of the V4L-DVB drivers. The
> >> Technotrend C-1501 drivers are unable to get a lock on 388Mhz (and a
> > couple
> >> of other frequencies, like 682Mhz and 322Mhz, but I can only test
> > 388Mhz).
> >>
> >> The dmesg will mention an I2C timeout when this occurs, I'm not sure if
> > its
> >> related (as it'll randomly give those timeouts when viewing working
> >> channels too).
> >>
> >> I have two seperate installs of Linux (Ubuntu 8.04 64-Bit with 1
> > received
> >> and Ubuntu 8.04 32-Bit with 2 receivers) which both suffer the same
> >> inability to lock onto that frequency. So its unlikely to be a hardware
> >> problem, also the Windows drivers do not seem to have any issues.
> >>
> >> Is anyone looking into this issue? If not, what would be the place to
> >> experiment?
> >>
> >> Gr,
> >>
> >> Jerremy Koot
> >>
> >>
> >>
> >> _______________________________________________
> >> linux-dvb mailing list
> >> linux-dvb at linuxtv.org
> >> http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
> >>
>
>
>
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