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

klaas de waal klaas.de.waal at gmail.com
Tue Mar 24 23:14:11 CET 2009


On Fri, Feb 27, 2009 at 6:35 AM, hermann pitton <hermann-pitton at arcor.de>wrote:

> Hi,
>
> Am Mittwoch, den 25.02.2009, 20:42 +0000 schrieb erik:
> > klaas de waal <klaas.de.waal <at> gmail.com> writes:
> > >
> > > On Fri, Oct 10, 2008 at 2:36 AM, hermann pitton <hermann-pitton <at>
> arcor.de>
> > wrote:
> > > Hi,
> > > Am Donnerstag, den 09.10.2008, 22:15 +0200 schrieb klaas de waal:
> > >  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},
> > > > #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
> > > >
> >
> > Hi Klaas/Hermann
> >
> > Your fix works perfectly for me as well. Prior I could not get the
> channels in
> > the 386750000 freq. With Fix appied my Ziggo locking issues disappeared.
> >
> > Is there any chance to get it into the official version?
> >
> > Erik
> >
>
> yes, there should be one for the later patch with the separate tuning
> table for tda8274a DVB-C I think.
>
> Patch for a review must be against recent mercurial v4l-dvb, needs to be
> in form of a unified diff, with mercurial installed and v4l-dvb cloned
> "hg diff > tda827x_dvb-c_improved-tuning-table.patch" something does
> create it most simple.
>
> Needs to go to linux-media at vger.kernel.org , please try README.patches
> in the v4l-dvb Documentation. Needs a Signed-off-by line.
>
> Also testers like you should provide a Tested-by line to promote it.
>
> Don't know if somebody has the tuning table for that specific tuner,
> tda8274a IIRC, or if this will only rely on the reports of the testers.
>
> Some equivalent of lna config = 0 needs to be introduced too to keep it
> quiet was said as well.
>
> Cheers,
> Hermann
>
>
>
> Hi Hermann,

Thanks for your "howto" on making a proper patch.
After a "make commit" in my local v4l-dvb tree, and filling in the template
I got the following output. I confess I do not know if this has now ended up
somewhere in linuxtv.org or that it is just local.
However, here it is:

changeset:   11143:f10e05176a88
tag:         tip
user:        Klaas de Waal <klaas.de.waal at gmail.com>
date:        Tue Mar 24 22:59:44 2009 +0100
files:       linux/drivers/media/common/tuners/tda827x.c
linux/drivers/media/dvb/ttpci/budget-ci.c
description:
Separate tuning table for DVB-C solves tuning problem at 388MHz.

From: Klaas de Waal <klaas.de.waal at gmail.com>

TechnoTrend C-1501 DVB-C card does not lock on 388MHz.
I assume that existing frequency table is valid for DVB-T. This is suggested
by the name of the table: tda827xa_dvbt.
Added a table for DVB-C with the name tda827xa_dvbc.
Added runtime selection of the DVB-C table when the tuner is type FE_QAM.
This should leave the behaviour of this driver with with DVB_T tuners
unchanged.
This modification is in file tda827x.c

The tda827x.c gives the following warning message when debug=1 :
tda827x: tda827x_config not defined, cannot set LNA gain!
Added a tda827x_config struct in budget-ci.c to get rid of this message.

Priority: normal

Signed-off-by: Klaas de Waal <klaas.de.waal at gmail.com>


I have attached the result of "hg diff > tda827x_dvb-c_tuning_table.patch.
Patch is with the "hg clone" done 23 march.
Tested with Linux kernel 2.6.28.9.

Cheers,
Klaas.
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