Linux/Sparc audio

[Rockin'Sound for your Sparc
Everything you wanted to know about audio for Sun SparcStations and clones running Linux, and then some.

Linux/Sparc audio drivers

Linux/Sparc is at the forefront of audio support for free operating systems for the Sparc platform. Why? Because we like music just as much as you do. (Me more than most, perhaps?) There's no reason you shouldn't be able to use your Sparc hardware every bit as fully in this respect as a PC (at least with the more recent systems.)

All you need to get started is a machine running one of the Linux distributions for Sparc processors. Grab an audio snapshot from, compile, set up devices, and start enjoying audio.

Heck, if you have a recent 2.2 or 2.3 kernel, you probably don't even need to do this, what you have should just work!

While some older kernels don't match the minor device assignments currently used, the audio snapshots do, and you should be using these anyway. All devices are character devices with major number 14.

mixer: 0
sequencer: 1 (not supported)
midi: 2 (not supported)
dsp: 3
audio: 4
dsp16: 5 (untested)
sndstat: 6 (not supported)
sequencer l2: 8 (not supported)
sndproc: 9 (not supported)

Additional sound devices are offset 16 (e.g. mixer1 is 16, audio1 is 20, etc.). The audioctl device is for compatibility with SunOS and Solaris, and allows only ioctls, not reading or writing. Its name is the audio device plus the string "ctl", so properly the audioctl device for the second audio card would be audio1ctl. audio0 and audio0ctl links to the first set of devices may be useful.

Sun audio applications expect that the AUDIODEV environment variable can be used to override the default /dev/audio choice.

Sparc audio hardware


Sun calls the audio hardware in the SS4, SS5 and the Ultras "audiocs". It supports monaural microphone and stereo line in, headphone, and line out ports. There is support for direct audio input from the internal cdrom on some systems; Sun claims NO UltraSparc systems support it, but I have not verified this. The SS10/LX speakerbox units do not work with this audio hardware. There is no way to determine if headphone or microphone are plugged in. The SS4 does not ship with audio support; Instead an add-on module must be purchased and installed. The SunMicrophone II (and not the I) is appropriate for use with this hardware. This microphone does not provide a battery like the older microphones, instead relying on the audio hardware to provide power.
Sparc machines with audiocs have a Crystal Semiconductor 4231A codec. Machines with an sbus use an APC (STP2024) DMA controller. PCI machines use the ebus for DMA.


The LX, SS10, and SS20, as well as the Tadpole Sparcbook 3 and the Sun SparcStation Voyager portables use dbri for audio. Some of these machines have onboard isdn provided by the DBRI. Most DBRI-equipped systems have an interface for the Sun SpeakerBox. It provides a speaker, and stereo line out, stereo line in, stereo headphone, and monaural microphone connections. LX systems also have a codec onboard (SpeakerBoxes have one integral) and so can be used without the SpeakerBox. The onboard interface lacks line in and line out support. DBRI systems should utilize the SunMicrophone I.
Sparc machines with dbri have an AT&T T5900FC isdn interface. LX machines and Sun SpeakerBoxes have Crystal Semiconductor 4215 codecs. The 4215 uses a time-based data transfer mechanism with pipes fed by the DBRI.

AMD 79c30

All sun4c machines, the SparcServer 6xx series, and the SparcClassic use the AM79C30A Digital Subscriber Controller (an isdn chip) for audio. Machines provide connectors for microphone and headphone. The 79c30 supports only monaural audio; Some machines also have an onboard monaural speaker.
As I already mentioned, the 79C30 is actually an isdn controller that Sun used for audio on these machines. It uses byte-at-a-time data transfer, which effectively makes it very slow.


If you didn't get it above, here's the info in table form.
For some reason Lynx hates these tables. I apologize.

Who's got what

Model amd dbri 4231(apc) 4231(ebus)
sun4c pizza boxes
SS1 X      
SS1+ X      
SS2 X      
sun4c monitor boxes
SLC X      
ELC X      
sun4c cake boxes
IPC X      
IPX X      
sun4m cake boxes
Classic (LC) X      
LX (ZX)   X    
sun4m portables
Voyager   X    
sun4m pizza boxes
10   X    
20   X    
4     X*  
5     X  
sun4u deep dish pizza boxes
Ultra 1     X  
Ultra 2     X  
sun4u pci machines
Ultra 5       X
Ultra 10       X
Ultra 30       X
Ultra 60       X
* - Requires purchase of SS4 audio module.

Support in Linux/Sparc

audio hardware kernel version dma play record 16 bit isdn
amd 79c30 2.2   X X   X
amd 79c30 2.3   X X   X
dbri 2.2   X      
dbri 2.3   X      
cs4231 (ebus dma) 2.2 X X X X  
cs4231 (ebus dma) 2.3 X X X X  
cs4231 (apc dma) 2.2 X X X X  
cs4231 (apc dma) 2.3 X X X X  

State of audio support

We currently have: The OSS mixer ioctl support was heavily reworked in August 1999 to behave more like a PC, and to simply behave better. Control of each input and output is now possible using e.g. aumix.

The SunOS emulation allows raplayer to work; Hopefully rvplayer (5.0) will work under Solaris emulation.

Linux/Sparc audio info in a Sun world

While I won't say I "miss" audio on my SunOS machine, there were certain tools it had that I really liked. One was audiotool. Another were the play/record that the audio demos had. The really useful one, especially now that we have a dummy audio driver which you can cat from, is raw2audio.

Currently I use audioctl as a replacement for audiotool. It's ported from the NetBSD version of same, with slight changes for SparcLinux.
tplay makes a nice replacement for play, but sadly does not come with trecord. One of these days...
raw2audio is a small wrapper around sox which will put an AU header on a raw audio file.

Linux/Sparc audio people

The folks responsible for the bulk of what's present in the Linux/Sparc audio subsystem are:
Tom Dyas
Wrote amd driver and audio midlevel.
Rudolf Koenig
Implemented (incomplete but substantial) DBRI driver.
Brent Baccala
Redesigned significant portion of amd driver to accomodate ISDN; Completing DBRI driver and working on ISDN support.
David Miller
Did most of the work on the cs4231/ebus driver.
Daria Brashear
Wrote cs4231 driver; Rewrote portions of midlevel to support binary compatibility and DMA.

Other info

We don't have a monopoly on audio support for Sparc. The good folks who brought you NetBSD support the 4231/apc and the amd79c30 on their systems as well. If we can't put you behind the wheel of a Linux system today, please give them a try.

4Front Technology supports Linux/x86 and Solaris as well as other platforms.

You might also want to check out the Advanced Linux Sound Architecture project. It's a reasonable alternative to the support that comes bundled in the Linux kernel.

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Last update: November 8, 1998