[linux-dvb] Re: Newbie questions

[Bruno Prior <bruno@rpgd.uklinux.net>]

Sorry to restart this thread, but I'm now wanting to have another crack 
at getting my Nova-T working, after an enforced break due to pressures 
of work. I've found a little time to play with DVB this weekend, and 
scanned the list to see if there were any other tips I could try.

To recap, the card works under Windows, so my problem is not a hardware 
fault with the card. It works randomly on one linux setup and not at all 
on another. It's currently plugged into the one where it doesn't work at 
all (the other is my wife's, who doesn't want me messing too much with 
her computer).

I have now tried Gavin's advice and removed the Audigy to make sure 
there were no IRQ clashes. lspci -v and /proc/interrupts showed the card 
had IRQ 5 to itself, but it still returned the same errors.

I have tried the latest CVS snapshot drivers, the 1.0.0-pre1 drivers and 
the latest Metzler Bros drivers (1.1.6b). None of them offer an 
improvement. I have also checked out the latest dvbtune source from CVS. 
Whatever driver I use and whatever frequency I try to tune to, I get low 
Bit Error Rates (50 - 500) and high Signal Strength (12079) and SNR 
(50000+). But I still get "Nothing to read from fd_pat/fd_sdt" errors.

I have also tried building the latest 2.5 series kernel (2.5.62-ac1), as 
someone suggested that was the easiest way of getting DVB working. 
However, easy is not a word I would use for it. It requires me to 
replace some of my basic modutils (insmod, rmmod, modprobe etc.) with 
alternatives from another package, which I am loathe to do, in case it 
leaves my existing setup unusable.

A few thoughts:

1. I seem to have both the old and the new device structures under /dev. 
I have /dev/ost/ and /dev/dvb/adapter0/. Am I right in thinking the 
former is the old and the latter is the new? Some of the devices in 
/dev/ost have identical major and minor numbers to the devices in 
/dev/dvb/adapter0. Could that cause a problem? Should I delete /dev/ost?

2. I have learnt from advice related to the Terratec DAB tuner that 
linux does not play nicely with Via chipsets. Could there be a problem 
with the Nova-T and Via-based motherboards? Have other people got the 
Nova-T (or equivalent) working on Athlon/Via combinations?

3. What about device permissions? The old (ost) devices are world 
read-writeable (666). The new (dvb/adapter0) devices are only 
read-writeable by root (600). While I try to get this to work, I am 
running dvbtune as root, so there should not be a problem with 
permissions, but I am always suspicious that devfs (which Mandrake runs 
be default) is screwing things up.

Does anyone have any suggestions? Does it look like a hardware clash is 
responsible? All my systems are Via-based (except for my wife's), so 
it's going to cost me if this is the problem. If it really is a case of 
replacing the hardware, what would people recommend (in the UK)? Replace 
the motherboard (and probably CPU with it)? Or replace the Nova-T? And 
replace them with what?

Cheers,

Bruno Prior


Gavin Hamill wrote:
> On Sun, Jan 12, 2003 at 10:55:34PM +0000, Bruno Prior wrote:
>
> > I can't think of anything else to try. The two lines:
> >
> > Nothing to read from fd_pat
> > Nothing to read from fd_sdt
>
> This just means no valid Transport Stream was picked up. A Transport 
> stream contains both a PAT and SDT to describe what services are 
> available on this frequency.
>
> OK, there are only two things I can think of now, and both are clutching
> at straws....
>
> 1) IRQ conflicts... do an 'lspci -v' or 'cat /proc/interrupts' and make 
> sure nothing is sharing an IRQ.
>
> If there is a share, then do whatever you can to stop it happening - 
> remove all expansion cards except the Nova (or AGP gfx.. ;) ,disable USB
> / serial / parallel / all on-board stuff in the BIOS and try again. 
> If that still fails, put the Nova in a different PCI slot. 
> These sound really desperate, but there have been a few documented cases 
> on the list where this was the solution to weird problems - and although 
> they concern users with 2 or 3 DVB cards, it's still worth a try.
>
> 2) Try the card in Windows! Make sure you don't actually have a duff 
> one! :)
>
> It's a bizarre install - Windows installs it as a Network device - and 
> when I tried it, I ended up having to set a static IP address for the 
> Nova card... Very shoddy.
>
> Cheers,
> Gavin.


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