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2004 Jul 11 20:24

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Re: [vox-tech] BTTV Problems with multiple cards
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Re: [vox-tech] BTTV Problems with multiple cards



On Sun, 11 Jul 2004, Hans W. Uhlig wrote:

> I purchased not long ago a new machine to function as
> a mythtivo and finished assembling it this weekend,
> sadly when I dropped in the three bt878a capture cards
> the unit just decides to spit out a greenscreen/static
> across the bus. If I rip out any 2 of the cards
> leaving just one it works fine.

What about leaving two cards in?  Does that do anything?  Try to place the
two cards in adjacent PCI slots, rather than two PCI slots that are apart
-- that minimizes the IRQ conflicts.  IRQ conflicts are generally not a
problem for PCI devices, but it *could* be a problem if you're using two
identical devices.

The other issue is the IO ports.  All devices have a limited IO ports that
they can use, and if all the available IO port ranges are used up, then
you'll end up with a conflict.  It's entirely possible the device was
designed to use only one range of IO ports (in which case you can't
install multiples of that card in one computer.)  To check for this,
install two of the cards, then try probing the PCI devices using `lspci
-vv`:

   # lspci -vv
   0000:02:08.0 Multimedia video controller: Brooktree Corporation Bt8...
   ...
   Region 0: Memory at f46fe000 (32-bit, prefetchable) [size=4K]
   ...

The above is the listing for my BT878 capture card.  Make sure none of the
"Region N" listed are same as other devices.  If some of them are same,
then you got a conflict, or the card wasn't designed to be installed in
multiples in a single computer.

If installing two cards works, and if the IRQ and the IO ranges conflict,
then try installing the third card.  Then work out the IRQ and the IO at
that time, for three card scenario.  Take it one step at a time -- two
cards first, then the third.

[snip]
> Also one other thing to note is while running on one
> card only it spits out these messages periodically
>
> bttv0: timeout: drop=64 irq=97874/97876,
> risc=1490e07c, bits: HSYNC OFLOW FDSR
> bttv0: reset, reinitialize

I've never seen that on my BT878...

BTW, what program are you using to view the TV signals?  What commands?
Make sure you're using /dev/video0 for the first video device, /dev/video1
for the second, and /dev/video2 for the third.  (I use `xawtv`, and I type
`xawtv -c /dev/video1` for the second video.)

Also, make sure you're not using the Xv extension on the second and third
instances of the TV signal viewing program, because only one application
is allowed to use Xv at any given time.  Most likely you'll have to
explicitely tell the program not to use Xv extension (I use `xawtv`, and I
type `xawtv -noxv` to turn off the Xv extension.  To combine with the
above command, you'd type `xawtv -noxv -c /dev/video1` to view the second
TV signal, `xawtv -noxv -c /dev/video2` for the third TV signal.)

-Mark


-- 
Mark K. Kim
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