Re: Trying to Make a SBAWE64 ISA Card Work in Wheezy
deloptes <deloptes@gmail.com> writes:
> [1] http://www.tldp.org/LDP/LG/issue38/blanchard.html
> [2] http://tldp.org/HOWTO/Plug-and-Play-HOWTO-11.html
> [3] http://people.freebsd.org/~tanimura/docs/4236b.pdf
I have had time to digest the information in those 3
links and must say thank you for posting them. I now have a much
better understanding of why I have always had trouble getting ISA
sound cards, even the really good ones, to work under Linux
sound. As I said once before in an earlier posting, when Linux
sound works, it works extremely well so I have nothing but good
things to say about it in general.
I am now amazed that the ISA cards ever worked at all for
any card other than Card 0. I also can see why there were
problems with maintaining card order after rebooting even with
udev rules in /etc/modprobe.d/alsa-base.conf. The problem
basically boils down to not having enough resources free to let
each card operate it's DMA access lines and interrupt request
line without stepping all over the other card or cards.
On the system I was trying to use, earlier versions of
Linux allowed a PCI and ISA-style card to coexist but not totally
peacefully. If Card 0 had audio on it, Card 1 still worked but
you could hear rhythmic pops which, while not terribly loud,
shouldn't have been there at all. I suspect that it was DMA
contention as I think they did get 2 different interrupts.
I believe that wheezy and the newer versions of Linux
sound are right in making it harder to bend things even if the
results are not what we always want since the idea is to have
stability and predictability. I will put a USB card on here and
declare victory.
This box is used to record 4 independent 8-bit audio
channels at 8-KHZ sampling. That is positively horrible for music
or high-quality voice but for VHF and UHF scanner radios, that is
approximately the frequency range of audio one gets so it all
sounds better than one might think.
Maybe my ears are just shot but seriously, the radios
sound quite normal but good sound such as music or broadcast
audio is muddy and Mr. Nyquist is laughing as he spins in his
grave.
Martin McCormick
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