[linux-dvb] Re: Ideas Wanted: Grundig STB Works, Nova-T Doesn't

[Martin Smith <martin@spamcop.net>]

>> I've been trying to get a Nova-T card to work for the last couple of
>> weeks and been having real problems. I've got 2 different versions of
>> this hardware, one with a Grundig tuner and one with the TDA10045.
>> With both cards I get a badly corrupted picture on all but one mux
>> (Crystal Palace transmitter).

> Hmm, both were "budget" type cards, right? The data transfer on these cards
> is a bit time critical... And to make things worse, there are still
> chipsets being produced which are apparently not fully PCI capable: I
> recently tried my TDA10045 card in a P4 machine with a SIS motherboard
> chipset and found that when the SAA7146A used PCI bursts of more than 16
> DWORDs, I would end up with CORRUPTED data in system memory. It seems to
> still hold true that only Intel can produce properly working PCI
> chipsets...

That's interesting. Is there any way to prove where the corruption is happening?
I guess if it's between PCI and main memory then it's very difficult to do this.

> So - what's you PCI chipset, CPU, etc? And about that one mux you can
> receive correctly, do its DVB-T parameters differ from the other ones?
> Maybe it has a stronger error correction, so that its net data rate is
> less, making it barely possible for your motherboard chipset to work
> properly...?

My test system is an Intel PIII 1GHZ with an Intel PIIX4 chipset and 768MB of
RAM. It's maybe getting a bit long in the tooth but it's been stable for a long
time.

The machine that will be the eventual home for the cards is my analogue MythTV
box, an Athlon 1800XP with Via chipset. I was hoping not to have to touch this
until I had the card working in the test box.

Your ideas on the Mux parameters may be a factor. I don't have a complete set of
behaviour on all the available muxes at the moment so I won't confuse the issue
by posting my speculations.

I hadn't considered the PCI timing issues you mentioned. I guess I'll
investigate lower level things than I've been doing, poke about in the BIOS, run
some memory tests and maybe try the card in the Athlon machine.

Thanks for the information,

Martin


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