introduction

linux-2.6.15.6

2.  remove the sound modules from /etc/modprobe.conf
3.  move the sound modules from /lib/modules/<kernel>/misc
    (for example, I make a /lib/modules/<kernel>/misc/tmp
    directory and copy the sound module files to that 
    directory).


Multiple Sound Cards:
=====================

The sound drivers will support multiple sound cards and there
are some great applications like multitrack that support them.  
Typically, you need two sound cards of different types.  Note, this
uses more precious interrupts and DMA channels and sometimes 
can be a configuration nightmare.  I have heard reports of 3-4
sound cards (typically I only use 2).  You can sometimes use
multiple PCI sound cards of the same type.

On my machine I have two sound cards (cs4232 and Soundblaster Vibra
16).  By loading sound as modules, I can control which is the first
sound device (/dev/dsp, /dev/audio, /dev/mixer) and which is 
the second.  Normally, the cs4232 (Dell sound on the motherboard) 
would be the first sound device, but I prefer the Soundblaster.  
All you have to do is to load the one you want as /dev/dsp 
first (in my case "sb") and then load the other one
(in my case "cs4232").

If you have two cards of the same type that are jumpered 
cards or different PnP revisions, you may load the same 
module twice.  For example, I have a SoundBlaster vibra 16
and an older SoundBlaster 16 (jumpers).  To load the module
twice, you need to do the following:

1.  Copy the sound modules to a new name.  For example
    sb.o could be copied (or symlinked) to sb1.o for the
    second SoundBlaster.

2.  Make a second entry in /etc/modprobe.conf, for example,
    sound1 or sb1.  This second entry should refer to the
    new module names for example sb1, and should include
    the I/O, etc. for the second sound card.

3.  Update your soundon.sh script, etc.

Warning:  I have never been able to get two PnP sound cards of the
same type to load at the same time.  I have tried this several times
with the Soundblaster Vibra 16 cards.  OSS has indicated that this
is a PnP problem....  If anyone has any luck doing this, please 
send me an E-MAIL.  PCI sound cards should not have this problem.a
Since this was originally release, I have received a couple of 
mails from people who have accomplished this!

NOTE: In Linux 2.4 the Sound Blaster driver (and only this one yet)
supports multiple cards with one module by default.
Read the file 'Soundblaster' in this directory for details.


Sound Problems:
===============

First RTFM (including the troubleshooting section 
in the Sound-HOWTO). 

1)  If you are having problems loading the modules (for
    example, if you get device conflict errors) try the
    following:

  A)  If you have Win95 or NT on the same computer,  
      write down what addresses, IRQ, and DMA channels
      those were using for the same hardware.  You probably 
      can use these addresses, IRQs, and DMA channels.
      You should really do this BEFORE attempting to get
      sound working!
  
  B)  Check (cat) /proc/interrupts, /proc/ioports,
      and /proc/dma.  Are you trying to use an address,
      IRQ or DMA port that another device is using?
  
  C)  Check (cat) /proc/isapnp
  
  D)  Inspect your /var/log/messages file.  Often that will 
      indicate what IRQ or IO port could not be obtained.
  
  E)  Try another port or IRQ.  Note this may involve 
      using the PnP tools to move the sound card to 
      another location.  Sometimes this is the only way 
      and it is more or less trial and error.

2)  If you get motor-boating (the same sound or part of a 
    sound clip repeated), you probably have either an IRQ
    or DMA conflict.  Move the card to another IRQ or DMA
    port.  This has happened to me when playing long files 
    when I had an IRQ conflict.

3.  If you get dropouts or pauses when playing high sample
    rate files such as using mpg123 or x11amp/xmms, you may 
    have too slow of a CPU and may have to use the options to 
    play the files at 1/2 speed.  For example, you may use
    the -2 or -4 option on mpg123.  You may also get this
    when trying to play mpeg files stored on a CD-ROM
    (my Toshiba T8000 PII/366 sometimes has this problem).

4.  If you get "cannot access device" errors, your /dev/dsp
    files, etc. may be set to owner root, mode 600.  You 
    may have to use the command:
      chmod 666 /dev/dsp /dev/mixer /dev/audio

5.  If you get "device busy" errors, another program has the
    sound device open.  For example, if using the Enlightenment
    sound daemon "esd", the "esd" program has the sound device.
    If using "esd", please RTFM the docs on ESD.  For example,
    esddsp <program> may be used to play files via a non-esd
    aware program.

6)  Ask for help on the sound list or send E-MAIL to the
    sound driver author/maintainer.

7)  Turn on debug in drivers/sound/sound_config.h (DEB, DDB, MDB).

8)  If the system reports insufficient DMA memory then you may want to
    load sound with the "dmabufs=1" option. Or in /etc/conf.modules add
	
	preinstall sound dmabufs=1

    This makes the sound system allocate its buffers and hang onto them.

    You may also set persistent DMA when building a 2.4.x kernel.


Configuring Sound:
==================

There are several ways of configuring your sound:

1)  On the kernel command line (when using the sound driver(s)
    compiled in the kernel). Check the driver source and
    documentation for details.

2)  On the command line when using insmod or in a bash script
    using command line calls to load sound.

3)  In /etc/modprobe.conf when using modprobe.

4)  Via Red Hat's GPL'd /usr/sbin/sndconfig program (text based).

5)  Via the OSS soundconf program (with the commercial version
    of the OSS driver.

6)  By just loading the module and let isapnp do everything relevant
    for you. This works only with a few drivers yet and - of course -
    only with isapnp hardware.

And I am sure, several other ways.  

Anyone want to write a linuxconf module for configuring sound?


Module Loading:
===============

When a sound card is first referenced and sound is modular, the sound system
will ask for the sound devices to be loaded. Initially it requests that
the driver for the sound system is loaded. It then will ask for 
sound-slot-0, where 0 is the first sound card. (sound-slot-1 the second and
so on). Thus you can do

alias sound-slot-0 sb

To load a soundblaster at this point. If the slot loading does not provide
the desired device - for example a soundblaster does not directly provide
a midi synth in all cases then it will request "sound-service-0-n" where n
is

  0	Mixer

  2  	MIDI

  3, 4	DSP audio


For example, I use the following to load my Soundblaster PCI 128
(ES 1371) card first, followed by my SoundBlaster Vibra 16 card,
then by my TV card:

# Load the Soundblaster PCI 128 as /dev/dsp, /dev/dsp1, /dev/mixer
alias sound-slot-0 es1371

# Load the Soundblaster Vibra 16 as /dev/dsp2, /dev/mixer1
alias sound-slot-1 sb
options sb io=0x240 irq=5 dma=1 dma16=5 mpu_io=0x330

# Load the BTTV (TV card) as /dev/mixer2
alias sound-slot-2 bttv
alias sound-service-2-0 tvmixer

pre-install bttv  modprobe tuner ; modprobe tvmixer
pre-install tvmixer modprobe msp3400; modprobe tvaudio 
options tuner debug=0 type=8 
options bttv  card=0 radio=0 pll=0


For More Information (RTFM):
============================
1)  Information on kernel modules: manual pages for insmod and modprobe.

2)  Information on PnP, RTFM manual pages for isapnp.

3)  Sound-HOWTO and Sound-Playing-HOWTO.

4)  OSS's WWW site at http://www.opensound.com.

5)  All the files in Documentation/sound.

6)  The comments and code in linux/drivers/sound.

7)  The sndconfig and rhsound documentation from Red Hat.

8)  The Linux-sound mailing list:  [e-mail].

9)  Enlightenment documentation (for info on esd)
    http://www.tux.org/~ricdude/EsounD.html.

10) ALSA home page:  http://www.alsa-project.org/


Contact Information:
====================
Wade Hampton:  ([e-mail])