Configuring Linux to support sound involves the following steps:
The next sections will cover each of these steps in detail.
Follow the manufacturer's instructions for installing the hardware or have your dealer perform the installation.
Older sound cards usually have switch or jumper settings for IRQ, DMA channel, etc; note down the values used. If you are unsure, use the factory defaults. Try to avoid conflicts with other devices (e.g. ethernet cards, SCSI host adaptors, serial and parallel ports) if possible.
When initially installing Linux you likely used a precompiled kernel. These kernels usually do not provide sound support. It is best to recompile the kernel yourself with the drivers you need. You may also want to recompile the kernel in order to upgrade to a newer version or to free up memory resources by minimizing the size of the kernel.
The Linux Kernel HOWTO should be consulted for the details of building a kernel. I will just mention here some issues that are specific to sound cards.
If you have never configured the kernel for sound support before it is a good idea to read all of the Readme files included with the kernel sound drivers, particularly information specific to your card type. The following documentation files can be found in the kernel sound driver directory, usually installed in /usr/src/linux/drivers/sound:
CHANGELOG - description of changes in each release COPYING - copying and copyright restrictions Readme - latest and most important news Readme.aedsp16 - information about Audio Excel DSP 16 sound card Readme.cards - notes on configuring specific cards Readme.linux - notes on installing separately release sound drivers Readme.modules - how to build driver as a loadable kernel module Readme.v30 - new features in version 3.0 sound driver experimental.txt - notes on experimental features
Follow the usual procedure for building the kernel. When you run
make config, enable sound support by answering "yes" to the
question
Sound card support?
At the end of the configuration questions a sound configuration program will be compiled, run, and will then ask you what sound card options you want. Be careful when answering these questions since answering a question incorrectly may prevent some later ones from being asked. For example, don't answer "yes" to the first question (PAS16) if you don't really have a PAS16. Don't enable more cards than you really need, since they just consume memory. Also some drivers (like MPU401) may conflict with your SCSI controller and prevent the kernel from booting.
I list here a brief description of each of the configuration dialog options. Answer "y" (yes) or "n" (no) to each question. The default answer is shown so that "(y/n)" means "y" by default and "(n/y)" means the default is "n". To use the default value, just hit Enter, but remember that the default value isn't necessarily correct.
Note also that all questions may not be asked. The configuration program may disable some questions depending on the earlier choices. It may also select some options automatically as well.
Answer "y" only if you have a Pro Audio Spectrum 16, ProAudio Studio 16 or Logitech SoundMan 16. Don't answer 'y' if you have some other card made by Media Vision or Logitech since they are not PAS16 compatible.
Answer "y" if you have an original SoundBlaster card made by Creative
Labs or a 100% hardware compatible clone (like the Thunderboard or SM
Games). If your card was in the list of supported cards look at the
card specific instructions in the Readme.cards file before
answering this question. For an unknown card you may answer "y'"if the
card claims to be SoundBlaster compatible.
Answer "y" if your card has a FM chip made by Yamaha (OPL2/OPL3/OPL4). Answering "y" is usually a safe and recommended choice, however some cards may have software (TSR) FM emulation. Enabling FM support with these cards may cause trouble (I don't currently know of any such cards, however).
Answer "y" if you have a GUS or GUS MAX. Answer "n" if you don't have a GUS since the driver consumes a lot of memory.
Be careful with this question. The MPU401 interface is supported by
almost all soundcards. However, some natively supported cards have
their own driver for MPU401. Enabling the MPU401 option with these
cards will cause a conflict. Also enabling MPU401 on a system that
doesn't really have a MPU401 could cause some trouble. If your card
was in the list of supported cards, look at the card specific
instructions in the Readme.cards file. It's safe to answer
"y" if you have a true MPU401 MIDI interface card.
It's safe to answer "n" to this question in all cases. The 6850 UART interface is very rarely used.
Answer "y" only if you have Orchid SW32, Cardinal DSP16 or some other card based on the PSS chipset (AD1848 codec + ADSP-2115 DSP chip + Echo ESC614 ASIC CHIP).
Answer "y" if you have installed the 16 bit sampling daughtercard on your GUS. Answer "n" if you have a GUS MAX. Enabling this option disables GUS MAX support.
Answer "y" only if you have a GUS MAX.
Again think carefully before answering "y" to this question. It's safe
to answer "y" if you have the original Windows Sound System card made
by Microsoft or Aztech SG 16 Pro (or NX16 Pro). Also you may answer
"y" in case your card was not listed earlier in this file. For cards
having native support in VoxWare, consult the card specific
instructions in Readme.cards. Some drivers have their own MSS
support and enabling this option will cause a conflict.
Answer "y" if you have a soundcard based on the Ensoniq SoundScape chipset. Such cards are being manufactured at least by Ensoniq, Spea and Reveal (Reveal makes other cards also).
Answer "y" if you have the AudioTriX Pro.
Answer "y" if your card has a Mozart (OAK OTI-601) or MAD16 (OPTi 82C928 or 82C929) audio interface chip. These chips are currently quite common so it's possible that many no-name cards have one of them. In addition the MAD16 chip is used in some cards made by known manufacturers such as Turtle Beach (Tropez), Reveal (some models) and Diamond (latest ones).
Enable this option if your card is a SoundBlaster Pro or SoundBlaster 16. Enable it also with any SoundBlaster Pro clones. Answering "n" saves some memory but "y" is the safe alternative.
Enable if you have a SoundBlaster 16 (including the AWE32).
Enable this if you have an Audio Excel DSP16 card. See the file
Readme.aedsp16 for more information.
The configuration program then asks some questions about the higher level services. It's recommended to answer "y" to each of these questions. Answer "n" only if you know you will not need the option.
Answering "n" disables /dev/dsp and /dev/audio, the
A/D and D/A converter devices. Answer "y".
Answering "n" disables /dev/midixx devices and access to any
MIDI ports using /dev/sequencer and /dev/music. This
option also affects any MPU401 and/or General MIDI compatible devices.
Answer "y" here.
Answering "n" disables /dev/sequencer and /dev/music
After the above questions the configuration program prompts for the
card specific configuration information. Usually just a set of I/O
address, IRQ and DMA numbers are asked. With some cards the program
asks for some files to be used during initialization of the
card. These are used by cards which have a DSP chip or microprocessor
which must be initialized by downloading a program (microcode) file to
the card. In some cases this file is written to a .h file by the
config program and then included to the driver during compile. Again,
read the information in the file Readme.cards pertaining to
your card type.
If you are upgrading from an older sound driver, make sure that the
files /usr/include/sys/soundcard.h and
/usr/include/sys/ultrasound.h are symbolic links to the
corresponding files in /usr/include/linux, or that they
simply contain the lines #include <linux/soundcard.h>
and #include <linux/ultrasound.h>, respectively.
You are now ready to compile and install the new kernel.
The first time the kernel sound driver is configured you need to
create the sound device files. The easiest way to do this is to cut
the short shell script from the end of the file Readme.linux
in the directory /usr/src/linux/drivers/sound, and run it as
user root.
If your device entries already exist, you might want to ensure they are correct. If they are not, or if you are in doubt, run the above script and it will replace any existing entries with correct ones.
Some older Linux distributions provided install scripts which created
incorrect sound device files. You may also have a
/dev/MAKEDEV script for creating device files. Using the
script included with the kernel sound driver is preferred since it
should always be up to date with the latest supported sound devices.
After running the script your sound device files should look something like this:
lrwxrwxrwx 1 root 11 Aug 22 00:01 audio -> /dev/audio0 crw-rw-rw- 1 root 14, 4 Aug 22 00:01 audio0 crw-rw-rw- 1 root 14, 20 Aug 22 00:01 audio1 lrwxrwxrwx 1 root 9 Aug 22 00:01 dsp -> /dev/dsp0 crw-rw-rw- 1 root 14, 3 Aug 22 00:01 dsp0 crw-rw-rw- 1 root 14, 19 Aug 22 00:01 dsp1 crw-rw-rw- 1 root 14, 2 Aug 22 00:01 midi00 crw-rw-rw- 1 root 14, 18 Aug 22 00:01 midi01 crw-rw-rw- 1 root 14, 34 Aug 22 00:01 midi02 crw-rw-rw- 1 root 14, 50 Aug 22 00:01 midi03 crw-rw-rw- 1 root 14, 0 Aug 22 00:01 mixer crw-rw-rw- 1 root 14, 16 Aug 22 00:01 mixer1 crw-rw-rw- 1 root 14, 8 Aug 22 00:01 music crw-rw-rw- 1 root 14, 17 Aug 22 00:01 patmgr0 crw-rw-rw- 1 root 14, 33 Aug 22 00:01 patmgr1 crw-rw-rw- 1 root 14, 1 Aug 22 00:01 sequencer lrwxrwxrwx 1 root 10 Aug 22 00:01 sequencer2 -> /dev/music crw-rw-rw- 1 root 14, 6 Aug 22 00:01 sndstat
If you are using the PC speaker sound driver, read the documentation that came with the package to determine what device files to create.
Normally the configuration you used when building the kernel will be
acceptable to the sound card driver. It is also possible to pass
parameters on the kernel command line (e.g. from LILO) to configure
the sound driver. These are defined in the file Readme.linux.
It should rarely be necessary to use these. They are mainly intended
for developers of Linux boot disks to create a kernel that supports
multiple types of sound cards.
You should now be ready to boot the new kernel and test the sound drivers. Follow your usual procedure for installing and rebooting the new kernel (keep the old kernel around in case of problems, of course).
During booting, check for a message such as the following on powerup (if they scroll by too quickly to read, you may be able to retrieve them with the "dmesg" command):
snd2 <SoundBlaster Pro 3.2> at 0x220 irq 5 drq 1
snd1 <Yamaha OPL-3 FM> at 0x388 irq 0 drq 0
This should match your sound card type and jumper settings (if any).
The driver may also display some error messages and warnings during boot. Watch for these when booting the first time after configuring the sound driver.
Next you should check the device file /dev/sndstat. Reading
the sound driver status device file should provide additional
information on whether the sound card driver initialized
properly. Sample output should look something like this:
% cat /dev/sndstat
VoxWare Sound Driver:3.0.1-950812 (Thu Aug 17 23:33:07 EDT 1995 root@fizzbin.ca)
Config options: 312002
Installed drivers:
Type 1: OPL-2/OPL-3 FM
Type 2: SoundBlaster
Card config:
SoundBlaster at 0x220 irq 5 drq 1
OPL-2/OPL-3 FM at 0x388 irq 0 drq 0
Audio devices:
0: SoundBlaster Pro 3.2
Synth devices:
0: Yamaha OPL-3
Midi devices: NOT ENABLED IN CONFIG
Timers:
0: System Timer
Mixers:
0: SoundBlaster
Now you should be ready to play a simple sound file. Get hold of a sound sample file, and send it to the sound device as a basic check of sound output, e.g.
% cat endoftheworld >/dev/dsp
% cat crash.au >/dev/audio
(Make sure you don't omit the ">" in the commands above).
Some sample sound files can be obtained from ftp://tsx-11.mit.edu/pub/linux/packages/sound/snd-data-0.1.tar.Z
Now you can verify sound recording. If you have sound input capability, you can do a quick test of this using commands such as the following:
# record 4 seconds of audio from microphone
% dd bs=8k count=4 </dev/audio >sample.au
4+0 records in
4+0 records out
# play back sound
% cat sample.au >/dev/audio
If these tests pass, you can be reasonably confident that the sound D/A and A/D hardware and software are working. If you experience problems, refer to the next section of this document.
If you still encounter problems after following the instructions in the HOWTO, here are some things to check. The checks are listed in increasing order of complexity. If a check fails, solve the problem before moving to the next stage.
You can check the date stamp on the kernel to see if you are running
the one that you compiled with sound support. You can do this with the
uname command:
% uname -a
Linux fizzbin 1.3.20 #1 Fri Aug 18 22:12:36 EDT 1995 i386
or by displaying the file /proc/version:
% cat /proc/version
Linux version 1.2.13 (root@fizzbin) (gcc version 2.6.3) #9 Sun Aug 6 11:56:47 EDT 1995
If the date stamp doesn't seem to match when you compiled the kernel,
then you are running an old kernel. Did you really reboot? If you use
LILO, did you re-install it (typically by running
/etc/lilo/install)? If booting from floppy, did you create a
new boot floppy and use it when booting?
You can see what drivers are compiled in by looking at
/proc/devices:
% cat /proc/devices
Character devices:
1 mem
4 tty
5 cua
6 lp
14 sound
15 Joystick
Block devices:
2 fd
3 hd
25 sbpcd
What we are looking for here is character device 14, labeled "sound". If the sound device is not listed then something went wrong with the kernel configuration or build. Start the installation process again, beginning with configuration and building of the kernel.
Make sure that the sound card was detected when the kernel booted. You
should have seen a message on bootup. If the messages scrolled off the
screen, you can usually recall them using the dmesg command:
% dmesg
or
% tail /var/adm/messages
If your sound card was not found then something is wrong. Make sure it really is installed. If the sound card works under DOS then you can be reasonably confident that the hardware is working, so it is likely a problem with the kernel configuration. Either you configured your sound card as the wrong type or wrong parameters, or your sound card is not compatible with any of the Linux kernel sound card drivers.
One possibility is that your sound card is one of the "compatible"
type that requires initialization by the DOS driver. Try booting DOS
and loading the vendor supplied sound card driver. Then soft boot
Linux using Control-Alt-Delete. Make sure that card I/O
address, DMA, and IRQ settings for Linux are the same as used under
DOS. Read the Readme.cards file from the sound driver source
distribution for hints on configuring your card type.
If your sound card is not listed in this document, it is possible that the Linux drivers do not support it. You can check with some of the references listed at the end of this document for assistance.
Try reading from the /dev/audio device using the dd
command listed earlier in this document. The command should run
without errors.
If this does not work, then a possible cause is the device file. Make
sure than the device files in the /dev directory has the
correct major and minor numbers as listed previously. Check that the
permissions on the device file allow reading and writing.
A remote possibility is a hardware problem. Try testing the drive under DOS, if possible, to determine if this could be the case.
If you still have problems, here are some final suggestions for things to try:
comp.os.linux or
other usenet newsgroupsEsc-x doctor