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[Download plain html version here: midi-howto.html]
This document's primary focus is the use of a MIDI interface to play external MIDI equipment under Linux.
This HOWTO is copyrighted 2002 Phil Kerr.
This document is distributed under the terms of the GNU Free Documentation License. You should have received a copy along with it. If not, it is available from:
http://www.fsf.org/licenses/fdl.html.
The official version of this document can be obtained from the Linux Documentation Project http://www.linuxdoc.org/.
The homepage for the most recent version of this HOWTO is: http://www.midi-howto.com
This HOWTO is an expansion of the MIDI-SB mini-HOWTO written by Hideki Saito. Many thanks for his contribution to the Linux community.
Many of the code samples contained in this HOWTO originated from the Linux Audio Developers (LAD) mailing list. Many thanks to them for allowing their inclusion.
Use the information in this document at your own risk.
I disavow any potential liability for the contents of this document.
Use of the concepts, examples, and/or other content of this document is entirely at your own risk.
All copyrights are owned by their owners, unless specifically noted otherwise.
Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark.
Naming of particular products or brands should not be seen as endorsements.
You are strongly recommended to take a backup of your system before major installation and backups at regular intervals.
MIDI is a set of hardware and software protocols used by electronic musical instruments to communicate. It was first released in 1982 and has become the de-facto communication standard between electronic musical instruments. The protocol specifies the physical hardware parameters for the cable and interfaces, and provides a well defined set of communication protocols to exchange musical and timing data.
Prior to MIDI there were several analog, and later basic digital, connection protocols. The earliest, circa. 1974, would transmit note information as a voltage though a wire from one keyboard to another. Later, 1980 - 1981, Roland created a basic digital protocol, DCB. The MIDI Manufacturers Association (MMA), working with the equipment manufacturers, defined a standard protocol and physical connection which allowed equipment from all complying manufacturers to connect and communicate with each other.
From 1985 MIDI interfaces started to appear on home computers and soon after sequencing programs appeared.
MIDI devices can be integrated into the soundcard or be a separate device. External MIDI interfaces may be attached to either the serial or USB port.
The first *and most important* thing you should do is check if your card is supported!
http://www.alsa-project.org/soundcards.php3
http://www.4front-tech.com/osshw.html
Configuring MIDI devices varies with Linux distributions. At it's most simplest a well supported card may be configured when you install the OS.
The Linux kernel includes the OSS drivers and in the 2.5 kernel the ALSA drivers. Most distributions provide a configuration tool (mostly for soundcards), but if you are using the MIDI port of a sound card it should be configured. Under RedHat you would use sndconfig, under SuSE yast, and Mandrake, DrakConf.
If none of the above tools will configure your MIDI interface, or you are experiencing problems, the following steps should be taken:
Does lsmod show any MIDI related modules? Here's a typical output from an OSS based system.
[root@beatbox]# lsmod
Module Size Used by
lockd 32208 1 (autoclean)
sunrpc 54640 1 (autoclean) [lockd]
autofs 9456 2 (autoclean)
usb-ohci 12624 0 (unused)
usbcore 43632 1 [usb-ohci]
hisax 470096 0 (autoclean) (unused)
isdn 104208 0 (autoclean) [hisax]
slhc 4544 0 (autoclean) [isdn]
eepro100 16144 1 (autoclean)
#---- Soundcard modules
opl3 11376 2
mad16 7968 1
ad1848 16848 1 [mad16]
sb 34752 1 [mad16]
uart401 6384 1 [mad16 sb]
sound 58368 0 [opl3 mad16 ad1848 sb uart401]
soundlow 464 0 [sound]
soundcore 2800 6 [sb sound]
nls_cp437 3952 2 (autoclean)
vfat 9408 1 (autoclean)
fat 30432 1 (autoclean) [vfat]
ide-scsi 7664 0
Look for mpu401, olp3, uart401 and oss.
If you are using USB devices don't forget to check if the USB modules are there.
To check the config cat the sndstat file:
[root@beatbox]# cat /dev/sndstat OSS/Free:3.8s2++-971130 Load type: Driver loaded as a module Kernel: Linux mega 2.2.17-21mdk #1 Thu Oct 5 13:16:08 CEST 2000 i686 Config options: 0 Installed drivers: Card config: Audio devices: 0: MAD16 WSS (82C930) (DUPLEX) Synth devices: 0: Yamaha OPL3 Midi devices: 0: Mad16/Mozart Timers: 0: System clock Mixers: 0: MAD16 WSS (82C930)
We see here that the MIDI device is a mad16 and this is listed in the lsmod output above.
If you see nothing related to MIDI check the contents of your /etc/modules.conf file.
[root@beatbox]# cat /etc/modules.conf
alias net-pf-4 ipx
pre-install pcmcia_core /etc/rc.d/init.d/pcmcia start
alias usb-interface usb-ohci
alias parport_lowlevel parport_pc
alias block-major-11 scsi_hostadapter
pre-install plip modprobe parport_pc ; echo 7 > /proc/parport/0/irq
alias scsi_hostadapter ide-scsi
alias eth0 eepro100
alias eth1 hisax
#---- Soundcard
alias sound-slot-0 mad16
options sound dmabuf=1
alias midi opl3
options opl3 io=0x388
options sb support=1
options mad16 io=0x530 irq=5 dma=0 dma16=1 mpu_io=0x300 mpu_irq=7 joystick=1
Here's the output of /proc/modules to check to see if the MIDI modules are loaded into the Kernel.
[root@mega /proc]# cat modules
0000-001f : dma1
0020-003f : pic1
0040-005f : timer
0060-006f : keyboard
0070-007f : rtc
0080-008f : dma page reg
00a0-00bf : pic2
00c0-00df : dma2
00f0-00ff : fpu
0170-0177 : ide1
01f0-01f7 : ide0
02f8-02ff : serial(auto)
#---- MIDI device
0300-0303 : MPU-401 UART
0376-0376 : ide1
0388-038b : Yamaha OPL3
03c0-03df : vga+
03f6-03f6 : ide0
03f8-03ff : serial(auto)
0530-0533 : MAD16 WSS config
0534-0537 : MAD16 WSS
de00-de1f : Intel Speedo3 Ethernet
f000-f007 : ide0
f008-f00f : ide1
You should see something similar to the above. If not you'll need to install MIDI drivers.
If you are going to be using ALSA 0.5x divers, I suggest a good read of Valentijn Sessink's Alsa-sound-mini-HOWTO which can be found at the link below:
http://www.linuxdoc.org/HOWTO/mini/Alsa-sound.html
For ALSA drivers later than 0.9x you should have a good read of the ALSA-HOWTO by Madhu Maddy.
http://www.alsa-project.org/alsa-doc/alsa-howto/
Below is a very quick install run-though for installing the ALSA 0.9 drivers and libs which is a required configuration for most MIDI apps.
[root@beatbox] # tar jxvf alsa-driver....tar.bz2 [root@beatbox] # cd alsa-driver..... [root@beatbox] # ./configure messages - no errors [root@beatbox] # make messages - no errors [root@beatbox] # make install messages - no errors [root@beatbox] # ./snddevices
Now you will need to edit /etc/modules.conf, or the ALSA file in your modules directory on some distributions. There may be entries for other, non-MIDI, devices, so be careful when you are editing the file.
A typical system may have old ALSA or OSS configurations in the file, you will need to remove, or better still comment them out.
Below is a typical modules.conf file showing the ALSA config with OSS.
alias char-major-116 snd alias char-major-14 soundcore alias snd-card-0 (MIDI/Sound card) alias sound-slot-0 snd-card-0 alias sound-service-0-0 snd-mixer-oss alias sound-service-0-1 snd-seq-oss alias sound-service-0-3 snd-pcm-oss alias sound-service-0-12 snd-pcm-oss
Change the (MIDI/Sound card) entry to that of your card. This information can normally be found on the ALSA website.
With the ALSA drivers installed, now you will need to install the header library files needed by ALSA based programs. This is what is contained in the alsa-libs package.
Make sure you have a matching pair of alsa-drivers and alsa-libs!
[root@beatbox] # tar jxvf alsa-libs....tar.bz2 [root@beatbox] # cd alsa-libs..... [root@beatbox] # ./configure messages - no errors [root@beatbox] # make messages - no errors [root@beatbox] # make install
Your system should now be configured :)
You can check this with a simple C program, if it compiles and can be executed then your system should be ok.
// Compile this test program like so: gcc alsatest.c -o alsatest -lasound
#include <stdio.h>
#include <alsa/asoundlib.h>
int main (int argc, char *argv[])
{
snd_seq_t *seq_handle;
if (snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
fprintf(stderr, "Error opening ALSA sequencer.\n");
exit(1);
}
printf("The ALSA libraries are installed.\n");
return 0;
}
MIDI is a real-time protocol and latency issues are a serious problem.
There are now several developers working on improving the latency times and improvements in the kernel are making Linux a fine platform for MIDI.
Although stock Linux distributions may run fine, pro set-ups should apply low-latency patches. More information can be found here:
http://www.gardena.net/benno/linux/audio/
Interest in Linux based MIDI is growing and this list will probably not reflect the true amount of MIDI software available, but should provide a reasonable selection of applications.
If you are developing, or know of, any other MIDI apps not listed here please drop me a note.
The Advanced Linux Sound Architecture is composed of several parts. The first is a fully modularized sound driver which supports module autoloading, devfs, isapnp autoconfiguration, and gives complete access to analog audio, digital audio, control, mixer, synthesizer, DSP, MIDI, and timer components of audio hardware. It also includes a fully-featured kernel-level sequencer, a full compatibility layer for OSS/Free applications, an object-oriented C library which covers and enhances the ALSA kernel driver functionality for applications (client/server, plugins, PCM sharing/multiplexing, PCM metering, etc.), an interactive configuration program for the driver, and some simple utilities for basic management.
OSS provides sound card drivers for most popular sound cards under Linux and FreeBSD. These drivers support digital audio, MIDI, synthesizers, and mixers found on sound cards. These sound drivers comply with the Open Sound System API specification. OSS provides a user-friendly GUI which makes the installation of sound drivers and configuration of sound cards very simple. It supports over 200 brand name sound cards, and provides automatic sound card detection, Plug-n-Play support, support for PCI audio soundcards, and support for full duplex audio.
Notemidi is a device driver for MIDI output via the RS-232 serial port on notebook/laptop computers. Notemidi can be used with the MIDIator MS-124W interface, Roland Sound Canvas sound modules, or Yamaha MU-x series sound modules.
http://www.michaelminn.com/linux/notemidi
KMid is an X11 / KDE based midi player for Linux and FreeBSD. It displays the text of karaoke files and changes its colour as it is being played so that the tune can be easily followed. KMid uses /dev/sequencer as output device supporting external synths, AWE , FM and GUS cards.
http://perso.wanadoo.es/antlarr/kmid.html
Pmidi is a straightforward command line program to play Midi files through the ALSA sequencer.
http://www.parabola.demon.co.uk/alsa/pmidi.html
TiMidity is a MIDI to WAVE converter that uses Gravis Ultrasound(*)-compatible patch files to generate digital audio data from General MIDI files. The audio data can be played through any sound device or stored on disk. On a fast machine, music can be played in real time.
http://www.goice.co.jp/member/mo/timidity/
Brahms is a sequencer and music notation program with several editing methods so far including Score-, Pianoroll-, Drum-, and Mastertrack Editors. For C++ programmers, it is easy to implement further editors by deriving from a general editor-class. MIDI Import and Export is also implemented. In combination with aRts-0.3.4, one can play wave-files and make use of the midibus to send midi-events to the software synthesizer.
Formerly known as KooBase
http://brahms.sourceforge.net/
Anthem is an advanced open source MIDI sequencer. Anthem allows you to record, edit and playback music using a sophisticated and acclaimed object oriented song technology.
http://anthem.sourceforge.net/
JAZZ++ is a full featured, audio capable midi sequencer for Linux and Windows.
http://www.jazzware.com/cgi-bin/Zope.cgi/jazzware/
UltiMusE-LX (the Ultimate Music Editor) is a composing program. No, it doesn't compose for you; it's a "word processor" for music. You draw sheet music on the screen using the mouse and/or computer keyboard. Up to 16 parts or voices fit on up to seven staves (staffs). Most standard musical notations are supported, as are MIDI instrument patch changes, events, and real-time clocks.
http://hometown.aol.com/knudsenmj/myhomepage/umuselx.htm
Melys is a Midi sequencer application for the Advanced Linux Sound Architecture (ALSA). Melys uses the sequencer support of ALSA, along with the GNOME libraries to produce a powerful and easy to use sequencer.
http://www.parabola.demon.co.uk/melys/
MidiMountain is a sequencer to edit standard MIDI files. Its easy-to-use interface should help beginners to edit and create MIDI songs (sequences), and it is designed to edit every definition known to standard MIDI files and the MIDI transfer protocol, from easy piano roll editing to changing binary system exclusive messages. http://www.midimountain.com/
MusE is a Qt 2.1-based MIDI sequencer for Linux with editing and recording capabilities. While the sequencer is playing you can edit events in realtime with the pianoroll editor or the score editor. Recorded MIDI events can be grouped as parts and arranged in the arrange editor. http://muse.seh.de/
Rosegarden is an integrated MIDI sequencer and musical notation editor. http://www.all-day-breakfast.com/rosegarden/
ttrk (tektracker) is a console MIDI sequencer with a tracker-style step editor. It is built for live playing, with convenient track mute buttons and loop control. ttrk supports both sending and syncing to MIDI clock pulses.
ShakeTracker aims to be a fully-featured MIDI sequencer with a tracker interface. It currently works well and supports most tracker effects. Anyone who has used Impulse Tracker before will feel at home, and for the new users, a simple but extensive help system is provided. Most commands and shortcuts resemble their tracker counterparts.
http://reduz.com.ar/shaketracker/
DrumPatterns is a free, open source, web oriented drum patterns generator, whose purpose is to help teach drum patterns. It can teach the rudiments as well as advanced rhythms. It can output characters, score, or Midi, and includes hours of samples.
http://www.linux-france.org/prj/drumpatterns/index-en.html
JSynthLib is an Open Source Universal Synthesizer Patch Editor / Librarian written in the Java Language. The project aims to eventually provide support for all existing Synthesizers by providing methods and documentation which allow users to develop drivers and editors for unsupported synths and contribute them to the project.
Spiral Synth is a physically modeled polyphonic analogue synthesizer. It is capable of creating the kind of sounds made by hardware analogue synths, the noises used in electronic music. You can also use it to make stranger sounds too. MIDI is supported, and it uses the standard OSS/Free sound output (/dev/dsp).
http://www.pawfal.org/SpiralSynth/
UltraMaster Juno-6 is a faithful virtual reproduction of a Roland Juno-6 Polyphonic Synthesizer. It features realtime 64-bit internal ULTRANALOG wave synthesis, an early 80's style arpeggiator and chorus, and 100s of patches to save your own custom settings. All parameters can be controlled in realtime, via on-screen GUI or external MIDI controllers.
http://www.ultramaster.com/juno6/index.html
Adds midi file support for x11amp (via timidity). A crude mixer interface is provided via the configuration dialog.
http://ban.joh.cam.ac.uk/~cr212/xmms-midi/
Sfront compiles MPEG 4 Structured Audio (MP4-SA) bitstreams into efficient C programs that generate audio when executed. MP4-SA is a standard for normative algorithmic sound, that combines an audio signal processing language (SAOL) with score languages (SASL, and the legacy MIDI File Format). Under Linux, sfront supports real-time, low-latency audio input/output, local MIDI input from soundcards, and networked MIDI input using RTP and SIP. A SIP server hosted on the Berkeley campus manages sessions. The website includes an online book about MP4-SA.
http://www.cs.berkeley.edu/~lazzaro/sa/index.html
jMax allows one to interactively design dataflow circuits. The basic data types that can go through are integers, symbols, lists, etc. It is an event-driven system and has been used for MIDI processing. A second part of the system (DSP) allows a continuous signal to flow through a circuit, which is most useful for PCM sound (ie. microphone, sound files, etc). The system is extensible by using shared libraries, you may add data processor types, data types, GUI elements, device types, and more. Data processors may also be designed as circuits and reused.
http://www.ircam.fr/equipes/temps-reel/jmax/
TSE3 is a powerful open source sequencer engine written in C++. It is a 'sequencer engine' because it provides the actual driving force elements of a sequencer but provides no form of user interface. Sequencer applications or multimedia presentation packages will incorporate the TSE3 libraries to provide a user with MIDI sequencing facilities.
KeyKit is a multi-tasking interpreted programming language (inspired by awk) designed exclusively for realtime and algorithmic MIDI manipulation. KeyKit's GUI provides several dozen tools for algorithmic music experimentation, including a multi-track sequencer and drum pattern editor. The GUI and all tools are completely written in the KeyKit language itself. This allows users to add new tools and operations to the existing tools, even while the system is running.
For those looking to develop MIDI applications, good examples are often needed to get you started.
The following examples were posted to the LAD mailing list in a thread about examples and documentation/tutorials.
Below is a little sample ALSA 0.9 sequencer client from Dr. Matthias Nagorni. It creates a writeable sequencer client and printf's any Pitchbender-, 7-Bit Controller- and Note-events on stderr.
More examples can be obtained from Matthias's site which is listed in the Links section.
You compile it like so:
[phil@beatbox] $ gcc seqdemo.c -o seqdemo -lasound
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
snd_seq_t *open_seq();
void midi_action(snd_seq_t *seq_handle);
snd_seq_t *open_seq() {
snd_seq_t *seq_handle;
int portid;
if (snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
fprintf(stderr, "Error opening ALSA sequencer.\n");
exit(1);
}
snd_seq_set_client_name(seq_handle, "ALSA Sequencer Demo");
if ((portid = snd_seq_create_simple_port(seq_handle, "ALSA Sequencer Demo",
SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE,
SND_SEQ_PORT_TYPE_APPLICATION)) < 0) {
fprintf(stderr, "Error creating sequencer port.\n");
exit(1);
}
return(seq_handle);
}
void midi_action(snd_seq_t *seq_handle) {
snd_seq_event_t *ev;
do {
snd_seq_event_input(seq_handle, &ev);
switch (ev->type) {
case SND_SEQ_EVENT_CONTROLLER:
fprintf(stderr, "Control event on Channel %2d: %5d \r",
ev->data.control.channel, ev->data.control.value);
break;
case SND_SEQ_EVENT_PITCHBEND:
fprintf(stderr, "Pitchbender event on Channel %2d: %5d \r",
ev->data.control.channel, ev->data.control.value);
break;
case SND_SEQ_EVENT_NOTEON:
fprintf(stderr, "Note On event on Channel %2d: %5d \r",
ev->data.control.channel, ev->data.note.note);
break;
case SND_SEQ_EVENT_NOTEOFF:
fprintf(stderr, "Note Off event on Channel %2d: %5d \r",
ev->data.control.channel, ev->data.note.note);
break;
}
snd_seq_free_event(ev);
} while (snd_seq_event_input_pending(seq_handle, 0) > 0);
}
int main(int argc, char *argv[]) {
snd_seq_t *seq_handle;
int npfd;
struct pollfd *pfd;
seq_handle = open_seq();
npfd = snd_seq_poll_descriptors_count(seq_handle, POLLIN);
pfd = (struct pollfd *)alloca(npfd * sizeof(struct pollfd));
snd_seq_poll_descriptors(seq_handle, pfd, npfd, POLLIN);
while (1) {
if (poll(pfd, npfd, 100000) > 0) {
midi_action(seq_handle);
}
}
}
Below is a ALSA 0.9 MIDI redirector by Nick Dowell.
/* ALSA Sequencer MIDI redirector.
Redirects the input to outputs determined by the MIDI channel
(as requested by Nathaniel Virgo on Linux-Audio-Dev ;-)
based on Dr. Matthias Nagorni's ALSA seq example
Nick Dowell <nixx@nixx.org.uk>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
int
main()
{
snd_seq_t *seq_handle;
snd_seq_event_t *ev;
int i;
int portid; /* input port */
int oportid[16]; /* output ports */
int npfd;
struct pollfd *pfd;
char txt[20];
if (snd_seq_open(&seq_handle, "hw", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
fprintf(stderr, "Error opening ALSA sequencer.\n");
exit(1);
}
snd_seq_set_client_name(seq_handle, "MIDI Redirect");
/* open one input port */
if ((portid = snd_seq_create_simple_port
(seq_handle, "Input",
SND_SEQ_PORT_CAP_WRITE | SND_SEQ_PORT_CAP_SUBS_WRITE,
SND_SEQ_PORT_TYPE_APPLICATION)) < 0) {
fprintf(stderr, "fatal error: could not open input port.\n");
exit(1);
}
/* open 16 output ports for the MIDI channels */
for (i=0; i<16; i++){
sprintf( txt, "MIDI Channel %d", i );
if ((oportid[i] = snd_seq_create_simple_port
(seq_handle, txt,
SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ,
SND_SEQ_PORT_TYPE_APPLICATION)) < 0) {
fprintf(stderr, "fatal error: could not open output port.\n");
exit(1);
}
}
npfd = snd_seq_poll_descriptors_count(seq_handle, POLLIN);
pfd = (struct pollfd *)alloca(npfd * sizeof(struct pollfd));
snd_seq_poll_descriptors(seq_handle, pfd, npfd, POLLIN);
while (1) /* main loop */
if (poll(pfd, npfd, 1000000) > 0){
do {
snd_seq_event_input(seq_handle, &ev);
snd_seq_ev_set_source( ev, oportid[ev->data.control.channel] );
snd_seq_ev_set_subs( ev );
snd_seq_ev_set_direct( ev );
snd_seq_event_output_direct( seq_handle, ev );
snd_seq_free_event(ev);
} while (snd_seq_event_input_pending(seq_handle, 0) > 0);
}
return 0;
}
Below is an example of writing data to the OSS /dev/midi interface by Craig Stuart Sapp.
More examples can be found at Craig's site listed in the Links section.
//
// Programmer: Craig Stuart Sapp [craig@ccrma.stanford.edu]
// Creation Date: Mon Dec 21 18:00:42 PST 1998
// Last Modified: Mon Dec 21 18:00:42 PST 1998
// Filename: ...linuxmidi/output/method1.c
// Syntax: C
// $Smake: gcc -O -o devmidiout devmidiout.c && strip devmidiout
//
#include <linux/soundcard.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
int main(void) {
char* device = "/dev/midi" ;
unsigned char data[3] = {0x90, 60, 127};
// step 1: open the OSS device for writing
int fd = open(device, O_WRONLY, 0);
if (fd < 0) {
printf("Error: cannot open %s\n", device);
exit(1);
}
// step 2: write the MIDI information to the OSS device
write(fd, data, sizeof(data));
// step 3: (optional) close the OSS device
close(fd);
return 0;
}
Below is a list of links to sites and resources covering MIDI and Linux.
http://www.bright.net/~dlphilp/linuxsound/ Sound & MIDI Software For Linux. A huge resource of MIDI and Audio related information.
http://www.linuxdj.com/audio/lad/ Linux Audio Developers mailing list. For developer related discussion.
http://www.linuxdj.com/audio/quality The Linux Audio Quality HOWTO. A good section on MIDI cards, essential reading for building a Linux studio.
http://www.alsa-project.org/ Alsa Project - Audio/MIDI Driver
http://www.4front-tech.com/ OSS - Audio/MIDI Driver
http://www.gardena.net/benno/linux/audio/ Low Latancy patches
http://ccrma-www.stanford.edu/~craig/articles/linuxmidi/ Introduction to MIDI programming in Linux. Craig Stuart Sapp covers writing basic MIDI utilities in C/C++ for the OSS driver.
http://www.suse.de/~mana Excellent collection of ALSA 0.9 MIDI and PCM example C programs by Dr. Matthias Nagorni.
As ever, a HOWTO is a work in progress. You are encouraged to give feedback on new applications and other interesting developments with MIDI under Linux.
MIDI cards are, by their wide variety, sometimes difficult to configure as they have various levels of driver support and configuration options. Your best source of reference for problems are ALSA's and OSS's websites, newsgroups, and if you get stuck please try searching the Linux Audio mailing lists.