readme.oss

linux-2.6.15.6

many users claim that sound quality in Linux is much worse than in DOS.
In addition some applications require 16 bit mode and they produce just
noise with a 8 bit only device.
- The card may work only in some cases but refuse to work most of the
time. The SB compatible mode always requires special initialization which is 
done by the DOS/Windows drivers. This kind of cards work in Linux after
you have warm booted it after DOS but they don't work after cold boot
(power on or reset).
- You get the famous "DMA timed out" messages. Usually all SB clones have
software selectable IRQ and DMA settings. If the (power on default) values
currently used by the card don't match configuration of the driver you will
get the above error message whenever you try to record or play. There are
few other reasons to the DMA timeout message but using the SB mode seems
to be the most common cause.

2. Trying to use a PnP (Plug & Play) card just like an ordinary sound card
--------------------------------------------------------------------------

Plug & Play is a protocol defined by Intel and Microsoft. It lets operating
systems to easily identify and reconfigure I/O ports, IRQs and DMAs of ISA
cards. The problem with PnP cards is that the standard Linux doesn't currently
(versions 2.1.x and earlier) don't support PnP. This means that you will have
to use some special tricks (see later) to get a PnP card alive. Many PnP cards
work after they have been initialized but this is not always the case.

There are sometimes both PnP and non-PnP versions of the same sound card.
The non-PnP version is the original model which usually has been discontinued
more than an year ago. The PnP version has the same name but with "PnP"
appended to it (sometimes not). This causes major confusion since the non-PnP
model works with Linux but the PnP one doesn't.

You should carefully check if "Plug & Play" or "PnP" is mentioned in the name
of the card or in the documentation or package that came with the card. 
Everything described in the rest of this document is not necessarily valid for
PnP models of sound cards even you have managed to wake up the card properly.
Many PnP cards are simply too different from their non-PnP ancestors which are
covered by this document.


Cards that are not (fully) supported by this driver
===================================================

See http://www.opensound.com/ossfree for information about sound cards 
to be supported in future. 


How to use sound without recompiling kernel and/or sound driver
===============================================================

There is a commercial sound driver which comes in precompiled form and doesn't
require recompiling of the kernel. See http://www.4Front-tech.com/oss.html for
more info.


Configuring PnP cards
=====================

New versions of most sound cards use the so-called ISA PnP protocol for
soft configuring their I/O, IRQ, DMA and shared memory resources.
Currently at least cards made by Creative Technology (SB32 and SB32AWE
PnP), Gravis (GUS PnP and GUS PnP Pro), Ensoniq (Soundscape PnP) and
Aztech (some Sound Galaxy models) use PnP technology. The CS4232/4236 audio
chip by Crystal Semiconductor (Intel Atlantis, HP Pavilion and many other
motherboards) is also based on PnP technology but there is a "native" driver
available for it (see information about CS4232 later in this document).

PnP sound cards (as well as most other PnP ISA cards) are not supported
by this version of the driver . Proper
support for them should be released during 97 once the kernel level
PnP support is available.

There is a method to get most of the PnP cards to work. The basic method
is the following:

1) Boot DOS so the card's DOS drivers have a chance to initialize it.
2) _Cold_ boot to Linux by using "loadlin.exe".  Hitting ctrl-alt-del
works with older machines but causes a hard reset of all cards on recent
(Pentium) machines.
3) If you have the sound driver in Linux configured properly, the card should
work now. "Proper" means that I/O, IRQ and DMA settings are the same as in
DOS. The hard part is to find which settings were used. See the documentation of
your card for more info.

Windows 95 could work as well as DOS but running loadlin may be difficult.
Probably you should "shut down" your machine to MS-DOS mode before running it.

Some machines have a BIOS utility for setting PnP resources. This is a good
way to configure some cards. In this case you don't need to boot DOS/Win95
before starting Linux.

Another way to initialize PnP cards without DOS/Win95 is a Linux based
PnP isolation tool. When writing this there is a pre alpha test version
of such a tool available from ftp://ftp.demon.co.uk/pub/unix/linux/utils. The
file is called isapnptools-*. Please note that this tool is just a temporary
solution which may be incompatible with future kernel versions having proper
support for PnP cards. There are bugs in setting DMA channels in earlier
versions of isapnptools so at least version 1.6 is required with sound cards.

Yet another way to use PnP cards is to use (commercial) OSS/Linux drivers.  See
http://www.opensound.com/linux.html for more info. This is probably the way you
should do it if you don't want to spend time recompiling the kernel and 
required tools.


Read this before trying to configure the driver
===============================================

There are currently many cards that work with this driver. Some of the cards
have native support while others work since they emulate some other
card (usually SB, MSS/WSS and/or MPU401). The following cards have native
support in the driver. Detailed instructions for configuring these cards
will be given later in this document.

Pro Audio Spectrum 16 (PAS16) and compatibles:
	Pro Audio Spectrum 16
	Pro Audio Studio 16
	Logitech Sound Man 16
	NOTE! The original Pro Audio Spectrum as well as the PAS+ are not
	      and will not be supported by the driver.

Media Vision Jazz16 based cards
	Pro Sonic 16
	Logitech SoundMan Wave
	(Other Jazz based cards should work but I don't have any reports
	about them).

Sound Blasters
	SB 1.0 to 2.0
	SB Pro
	SB 16
	SB32/64/AWE
		Configure SB32/64/AWE just like SB16. See lowlevel/README.awe
		for information about using the wave table synth.
	        NOTE! AWE63/Gold and 16/32/AWE "PnP" cards need to be activated
		      using isapnptools before they work with OSS/Free.
	SB16 compatible cards by other manufacturers than Creative.
		You have been fooled since there are _no_ SB16 compatible
		cards on the market (as of May 1997). It's likely that your card
		is compatible just with SB Pro but there is also a non-SB-
		compatible 16 bit mode. Usually it's MSS/WSS but it could also
		be a proprietary one like MV Jazz16 or ESS ES688. OPTi
		MAD16 chips are very common in so called "SB 16 bit cards"
		(try with the MAD16 driver).

	======================================================================
	"Supposed to be SB compatible" cards.
		Forget the SB compatibility and check for other alternatives
		first. The only cards that work with the SB driver in
		Linux have been made by Creative Technology (there is at least
		one chip on the card with "CREATIVE" printed on it). The
		only other SB compatible chips are ESS and Jazz16 chips
		(maybe ALSxxx chips too but they probably don't work).
		Most other "16 bit SB compatible" cards such as "OPTi/MAD16" or
		"Crystal" are _NOT_ SB compatible in Linux.

		Practically all sound cards have some kind of SB emulation mode
		in addition to their native (16 bit) mode. In most cases this
		(8 bit only) SB compatible mode doesn't work with Linux. If
		you get it working it may cause problems with games and
		applications which require 16 bit audio. Some 16 bit only
		applications don't check if the card actually supports 16 bits.
		They just dump 16 bit data to a 8 bit card which produces just
		noise.

		In most cases the 16 bit native mode is supported by Linux.
		Use the SB mode with "clones" only if you don't find anything
		better from the rest of this doc.
	======================================================================

Gravis Ultrasound (GUS)
	GUS
	GUS + the 16 bit option
	GUS MAX
	GUS ACE (No MIDI port and audio recording)
	GUS PnP (with RAM)

MPU-401	and compatibles
	The driver works both with the full (intelligent mode) MPU-401
	cards (such as MPU IPC-T and MQX-32M) and with the UART only
	dumb MIDI ports. MPU-401 is currently the most common MIDI
	interface. Most sound cards are compatible with it. However,
	don't enable MPU401 mode blindly. Many cards with native support
	in the driver have their own MPU401 driver. Enabling the standard one
	will cause a conflict with these cards. So check if your card is
	in the list of supported cards before enabling MPU401.

Windows Sound System (MSS/WSS)
	Even when Microsoft has discontinued their own Sound System card 
	they managed to make it a standard. MSS compatible cards are based on 
	a codec chip which is easily available from at least two manufacturers
	(AD1848 by Analog Devices and CS4231/CS4248 by Crystal Semiconductor).
	Currently most sound cards are based on one of the MSS compatible codec
	chips. The CS4231 is used in the high quality cards such as GUS MAX,
	MediaTrix AudioTrix Pro and TB Tropez (GUS MAX is not MSS compatible). 

	Having a AD1848, CS4248 or CS4231 codec chip on the card is a good
	sign. Even if the card is not MSS compatible, it could be easy to write
	support for it. Note also that most MSS compatible cards
	require special boot time initialization which may not be present
	in the driver. Also, some MSS compatible cards have native support.
	Enabling the MSS support with these cards is likely to
	cause a conflict. So check if your card is listed in this file before
	enabling the MSS support.

Yamaha FM synthesizers (OPL2, OPL3 (not OPL3-SA) and OPL4)
	Most sound cards have a FM synthesizer chip. The OPL2 is a 2
	operator chip used in the original AdLib card. Currently it's used
	only in the cheapest (8 bit mono) cards. The OPL3 is a 4 operator 
	FM chip which provides better sound quality and/or more available 
	voices than the OPL2. The OPL4 is a new chip that has an OPL3 and
	a wave table synthesizer packed onto the same chip. The driver supports
	just the OPL3 mode directly. Most cards with an OPL4 (like
	SM Wave and AudioTrix Pro) support the OPL4 mode using MPU401
	emulation. Writing a native OPL4 support is difficult
	since Yamaha doesn't give information about their sample ROM chip.

	Enable the generic OPL2/OPL3 FM synthesizer support if your
	card has a FM chip made by Yamaha. Don't enable it if your card
	has a software (TRS) based FM emulator.

	----------------------------------------------------------------
	NOTE! OPL3-SA is different chip than the ordinary OPL3. In addition
	to the FM synth this chip has also digital audio (WSS) and
	MIDI (MPU401) capabilities. Support for OPL3-SA is described below.
	----------------------------------------------------------------

Yamaha OPL3-SA1

	Yamaha OPL3-SA1 (YMF701) is an audio controller chip used on some
	(Intel) motherboards and on cheap sound cards. It should not be
	confused with the original OPL3 chip (YMF278) which is entirely
        different chip. OPL3-SA1 has support for MSS, MPU401 and SB Pro
	(not used in OSS/Free) in addition to the OPL3 FM synth.

	There are also chips called OPL3-SA2, OPL3-SA3, ..., OPL3SA-N. They
	are PnP chips and will not work with the OPL3-SA1 driver. You should 
	use the standard MSS, MPU401 and OPL3 options with these chips and to
	activate the card using isapnptools.

4Front Technologies SoftOSS

	SoftOSS is a software based wave table emulation which works with
	any 16 bit stereo sound card. Due to its nature a fast CPU is
	required (P133 is minimum). Although SoftOSS does _not_ use MMX
	instructions it has proven out that recent processors (which appear
	to have MMX) perform significantly better with SoftOSS than earlier
	ones. For example a P166MMX beats a PPro200. SoftOSS should not be used
	on 486 or 386 machines.

	The amount of CPU load caused by SoftOSS can be controlled by
	selecting the CONFIG_SOFTOSS_RATE and CONFIG_SOFTOSS_VOICES
	parameters properly (they will be prompted by make config). It's
	recommended to set CONFIG_SOFTOSS_VOICES to 32. If you have a
	P166MMX or faster (PPro200 is not faster) you can set
	CONFIG_SOFTOSS_RATE to 44100 (kHz). However with slower systems it
	recommended to use sampling rates around 22050 or even 16000 kHz.
	Selecting too high values for these parameters may hang your
	system when playing MIDI files with hight degree of polyphony
	(number of concurrently playing notes). It's also possible to
	decrease CONFIG_SOFTOSS_VOICES. This makes it possible to use
	higher sampling rates. However using fewer voices decreases
	playback quality more than decreasing the sampling rate.

	SoftOSS keeps the samples loaded on the system's RAM so much RAM is
	required. SoftOSS should never be used on machines with less than 16 MB
	of RAM since this is potentially dangerous (you may accidentally run out
	of memory which probably crashes the machine). 

	SoftOSS implements the wave table API originally designed for GUS. For
	this reason all applications designed for GUS should work (at least
	after minor modifications). For example gmod/xgmod and playmidi -g are
	known to work.

	To work SoftOSS will require GUS compatible
	patch files to be installed on the system (in /dos/ultrasnd/midi). You
	can use the public domain MIDIA patchset available from several ftp
	sites.

        *********************************************************************