RE: glitches, another story *g* - more results

[Plamen Ganev <pganev@com-it.net>]

> From: Guido Fiala [mailto:gfiala@s.netic.de]

> >> >I can confirm that heat is a problem. But, I get the glitches on cold
> >> >machine and card too. I need to isolate the problem better
> >> before reporting.
> >
> >Problem solved, but the solution is bad news...
> >
> >Apparently the DVB card doesn't like a K6-233 processor. It's
> that simple,
> >but took me days to understand.
>
> Think that's to easy - i have an P-2-450 and a lot of glitches -
> does it just
> work with P-1's or what? PCI-Bus-Clock related?

My problem was corruption in the received picture even without having to
record the stream to disk.

As I said in that message, I think there's an issue with the bus sharing
between the periferals and that the K6 was increasing this issue, while the
P-1 seemed to be unaffected. The K6 has a different way to access the bus,
so I presume it's placing the DVB card on hold way too much. Increasing the
speed of the CPU increases it's bus bandwidth demands, so ultimately makes
things worse. This is all I can think of.

Someone could object that Ralph's says that you're better with a high-speed
cpu than a slow one. I'm not saying the contrary. PII/PIII machines have a
completely different way to access their cache/ram/bus than the pentiums.

If the problem is related to clock skew, arbitration issues and so even a
slight change in the cpu/bus etc frequency can have impact.

But all this is just words, until someone hooks a logic analyzer on that bus
and sees what's going on.

I don't think that raw CPU power is an isssue. I refuse to think that I need
a PIII to send 2mbit of mpeg data from the card to the screen or from the
dvd to the card. A very old 486 can do better than that routing packets.

Regarding heat:

Yesterday, I enjoyed some 40minutes watching a perfect TV picture with a
closed PC case and then the picture suddently froze. I opened the case and
the DVB card was very hot (maybe my LNB is eating too much power, or maybe
it's just bad design). So I placed a nice 8cm fan on top of the card,
blowing straight on the tuner section and the dsp. After a couple of minutes
the picture started again (note: I did not reload the drivers). At first
there was some glitches (the sort of thing you get when there're missed
key-frames), then perfect. Today, it's been running now for 4 consecutive
hours with closed case and it's fine.

Plamen