[linux-dvb] Re: Hauppauge Nova-T Problems

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Edward Wildgoose" <ed@wildgooses.com>
> However, the picture is now jerky, it plays smoothly for a few frames,
> then hiccups, then plays smooth for a bit longer.  Appears to be 1-2
> hiccups a sec giving a kind of jerky progress to moving objects.
> Sound is out of sync as well.
>
> I guess after that I need to start disabling the onboard hardware and
> see if I can't get this card working.  But assuming that it is some
> kind of corruption on the PCI bus, then are there any tips on debugging
> this or preferably making things cooperate.  I tried bumping up the
> PCI latency on the dvb card to 128, however, this didn't appear to
> make any real difference...  Guess it's back to fiddling

FWIW, these are exactly the symptoms I had on a SIS chipset with a budget
card. These cards appear to be very timing sensitive. The parameters to
play with are the SAA7146A "FIFO threshold" and "PCI burst length"
settings. Settings I found to work well:

1. PCI burst = 32 DWORDs, FIFO threshold = 32 DWORDs - This one handles
even a 40Mbps DVB-Cable stream on both i440BX as well as i850E chipsets
(don't have others to try).

2. PCI burst = 16 DWORDs, FIFO threshold = 16 DWORDs - seems to work
equally well.

3. PCI burst = 16 DWORDs, FIFO threshold = 32 DWORDs - The only setting
which allowed me to make a DVB-T budget card work on a SIS 651 chipset.

> Just for reference this is an Asus P4P800 board.  I don't suppose that
> anyone else has one of these and could say that it works for them with a
> budget card?

I don't have any experience with the i875 chipset yet, so please try the
above settings and let us know if you find any combination that works on
this chipset!

> The full featured card works fine... (well apart from crashing
> frequently...)

The full featured card cannot pass an unfiltered MPEG-2 stream, and if it
passes MPEG-2 packets, those are not only lower data rates, but also
buffered by the AV7110, thus making the transfers much less timing
sensitive... So it's not surprising you are seeing PCI timing issues now
you did not have with the full featured card.

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany



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