Synopsis:
A easy quick fix for bt87x (and possibly other things) being loaded as card0 instead of the sound card you want to have as default. The fix appears to work for other devices like modems that are set as card 0.

The Fix: Add the module you don't want alsa to use to the blacklist for hotplug.

Full FIX instructions at bottom.

Introduction:
Several people have had a problem with alsa in slack 10. It seems alsa will pick their TV capture card as card 0 and put their sound card as card 1. This is a bad thing because card 0 is the default playback device for alsa.

After looking through various suggestions for a fix I was left unsatisfied. Some fixes include: altering alsa.conf default device settings (messy) making a asoundrc file and redefining the default device (treating the symptoms not the disease?), uninstalling alsa and rebuilding from source excluding the bt87x driver (time consuming but can work), and finally removing alsa and going oss (biting off your nose to... ).

The following fix will work given certain conditions are apply:
A: You use a patch cord to get sound from your capture card to your sound cards aux input for externally to line in OR You don't need to send sound from your capture card through your computer (aka you use external speakers only that are plugged directly into the capture card)
B: cat /proc/asound/cards shows card 0 as something other then your real soundcard (example bt87x).
C. your real sound card actually functions with alsa.

Background:
In anycase here is some background, in slackware 10.0 alsa driver loading does not appear to be performed directly by /etc/rc.d/rc.alsa . As a comments in rc.alsa indicate rc.alsa will only load alsa driver if something else hasn't already, and it mentions hotplug as the example. The modules.conf alsa entries seem to be superceded by the hotplug loading of alsa I have not tested this, but needless to say a entry in modules.conf like:
alias snd-card-0 snd-intel8x0
is ineffectual in getting alsa to load the correct card 0 at boot, thought manually modprobing the modules, as would be expected does.

Prefix Actions Taken:
installed slackware 10.0
ran alsamixer
controls appeared for bt87x
ran alsamixer -c 1
controls for real sound card appeared, if you have three cards then it may be -c 2

THE FIX:
0.
A. Run alsaconf
B. Pick the driver for your actual sound card, interestingly enough bt87x wasn't listed when prompted to pick the card driver.
* Zero step may not be necessary but I did as it gives your some entries in modules.conf my slack 10 install did not by default have any.

1. Edit /etc/hotplug/blacklist
example:
pico /etc/hotplug/blacklist

* this file is a list of modules that are not to be loaded by hotplug, for example you
will notice oss modules are all there. The syntax for the file is simple: "driver
namealone (without any spaces) on a line. Other lines are ignored."

2. Add the bt87x module to the list.
example:
# alsa has been a bad little boy
snd-bt87x

3. Save the file

4. reboot the computer or manual reinitialize
*note telinit 1 is not enough, if you want to manually reinitialize then you better know how too.

5. After reboot run alsamixer. The correct sound card should come up. Unmute if necessary. Master and pcm at least.

6. Hopefully you have sound now.

Conclusion:
The reason I like this fix is it was simple and did not require altering alsa. It may not work given some circumstances but it worked for me and two other people I helped in IRC. Hope it works for you too. This was tested on two systems with bt87x and one with some voice modem device autoset as card 0.



Appendix:

FYI When I was working on fixing my problem I used this manual way of getting sound to work *until you reboot* it is to run alsaconf (to get some module.conf entries) then modprobe -r snd-bt87x and snd-intel8x0 (my real sound card, yours may be different) and modprobe -r all snd-* entries if neccessary. then I modprobe snd-intel8x0 and ran alsamixer. sure enough alsa had loaded correctly as set in the modules.conf file with my nforce2 card as card0 and sound worked correctly. additionally cat /proc/asound/cards showed only this entry after manually modprobe starting alsa drivers:
0 [nForce2 ]: NFORCE - NVidia nForce2
NVidia nForce2 at 0xd9080000, irq 12

The reply I received from the alsa team for a similar problem with the modem was:
"Try to use module option like this in modules.conf

options snd-intel8x0 index=0
options snd-intel8x0m index=1 <--- insert BT87x module name here

This will swap soundcards and modem will be second."

Hey thanks joeinspirit, the fix worked perfect the first time. I have ATI TV Wonder VE and Sound Blaster Live Value, all is good with Slack 10 now!