[linux-dvb] knc1 DVB-S tuning issues

Julian Scheel julian at jusst.de
Tue Jul 19 20:40:37 CEST 2005

Hi Adriana,

Am Dienstag, 19. Juli 2005 14:43 schrieben Sie:
> We (deuromedia) have done the dvb support for itvmedia. We had the same
> tuning problems on ARD for a long time. Somebody at itvmedia asked Andrew
> de Quincey to take a look at this, but as far as I know, he didn't find a
> solution yet.
> There are no modifications to the driver, we use the sources from kernel
> 2.6.11.
> The "solving" of the tuning problem is actually this sequence:
> - try FE_DISEQC_SEND_MASTER_CMD / FE_SET_FRONTEND ioctls about 6 times
> each; - after every FE_SET_FRONTEND, read status 10 times;
> Between every ioctls, usleep (50000) - this interval I found somewhere in
> an old libdvb from Metzler brothers, IIRC.
> We had this problem most often on ARD (11836 MHz on astra), also sometimes
> on ZDF.vision (11954), but strangely, never on RTL (12188). First tuning
> operation after starting the machine was the most problematic (status 0x1f
> on ard after ~40 read_status operations, if we were lucky).
> We replaced the knc with a wintv nova, this one always reported a nice 0x1f
> at the first fe_read_status. So definately it was a problem with the card,
> not some external cause.

At first, I have to thank you for this detailled information!

That matches pretty good with my experience - I just had a talk to the 
technical director at KNC. He mentioned that it may be an agc-related 
problem. He'll provide me with some more specifications - may that'll help us 
fixing the problem.
I'll keep the list posted.

If anyone else has some further thoughts I'd like to hear them (c:


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