OSS

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Open Sound System (OSS) v4 is an alternative to ALSA as a layer between programs and sound hardware. Users of v3 are encouraged to use the not so maintained v4 version which has a BSD and GPL-2 licences.

Installation

Currently there is no maintained ebuild in portage for this software.

Kernel

KERNEL Sound card support
Device Drivers  --->
        <M> Sound card support  --->
             --- Sound card support
             < >   Advanced Linux Sound Architecture --->
             < >   Open Sound System (DEPRECATED)  --->

Ebuild

There are many more or less active overlays for ebuilds. Most of them require layman to have git or mercurial support:

root #echo 'app-portage/layman git mercurial' >> /etc/portage/package.use
root #emerge layman

angelos-overlay

angelos-overlay seems pretty up to date and maintained by a Gentoo developer. <3 Christoph
To use it:

root #layman -a angelos

bar-overlay

Warning
This overlay replaces up to date ebuilds in portage and doesn't follow the official guidelines for keywording. Not true anymore as of 2012/07/31 23:33.

To add the bar-overlay to layman, please follow the instructions on bar-overlay
There are USE flags in media-sound/oss::bar so that one can build selected drivers instead using the OSS_CARDS environment variable.

FILE /etc/portage/make.conf
OSS_CARDS="cmi878x cmpci hdaudio ich imux midiloop midimix usb userdev"

bug report

Ebuilds can also be found in bug #184123, which would need to be added to the local overlay

Install

Build the modules and add /etc/init.d/oss to the default runlevel:

root #emerge oss
root #rc-update add oss default

Configuration

General configuration after install.

Compatibility

  • Many application only provide support for ALSA, therefore it is a good idea to keep both USE flags
FILE /etc/portage/make.conf
USE="... alsa oss ..."

OSS will create ALSA devices for those applications.

Note
in the current ebuilds, this feature can be disabled using a USE flag like salsa or libalsa
  • to be able to use OSS4 with GNOME or other gstreamer dependent desktop environments like xfce4. Once again, media-plugins/gst-plugins-oss4 which is included in media-libs/gst-plugins-good! was dropped from the official tree, so you will have to make your own ebuild (quite easy for this one) or else grab one somewhere (bar-overlay, for example).
root #emerge --ask media-plugins/gst-plugins-oss4

CMI878x

Unlike ALSA, OSS4 has fewer complex options to configure, so you won't need any `soundon.user'. Especially if your setup isn't complex or are using more than one sound card. In the latter case, you may want to keep a `soundon.user' file to be able to choose your first card (default card). And then, insert a few lines correcting devices nodes which can be problematic.

#!/bin/sh
# $ID: /usr/lib/oss/soundon.user, 2012/07/27 12:57:40 -tclover Exp $
modprobe -a oss_{cmi878x,hdaudio}
/usr/sbin/ossdetect -diu
/usr/sbin/ossdevlinks 
# Remapping ossdevlinks links
if [ -d /dev/oss/oss_cmi878x ]; then
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp_ac3
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp_in
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp_mmap
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp_multich
	ln -sf /dev/oss/oss_cmi878x0/pcm1 /dev/dsp_out
	vmixctl attach /dev/oss/oss_cmi878x0/pcm1 /dev/oss/oss_cmi878x0/pcm1
else
	ln -sf /dev/oss/oss_hdaudio0/pcm0 /dev/dsp
	ln -sf /dev/oss/oss_hdaudio0/pcmin0 /dev/dsp_in
#	ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp
	ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp_ac3
#	ln -sf /dev/oss/oss_hdaudio0/spdin0 /dev/dsp_in
	ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp_mmap
	ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp_multich
	ln -sf /dev/oss/oss_hdaudio0/spdout0 /dev/dsp_out
#	vmixctl attach /dev/oss/oss_hdaudio0/pcm0 /dev/oss/oss_hdaudio0/pcmin0
fi
# vim:fenc=utf-8:ft=sh:ci:pi:sts=0:sw=2:ts=2:

The previous script will check if there are devices nodes, so a sound card, with CMI878x driver and then relink almost everything to it or else use HDAudio.

Note
Notice that, that file will be overridden whenever media-sound/oss is updated so you will have to add that file to:
FILE /etc/portage/make.conf
CONFIG_PROTECT="... /usr/lib/oss/soundon.user ..."

Or else, create a file like `~/.scripts/soundon.user' and edit `/etc/init.d/oss' to your liking.

FILE /etc/init.d/oss
/usr/sbin/soundon
/root/.scripts/soundon.user
/usr/sbin/savemixer -L

Now you can enjoy Open Sound System. I found the sound with OSS4 to be better than what I can get with ALSA. There was a time when my CMI878x sound works only with OSS4 but a few things changed.

OSS4 has its own mixer so using extra sound daemons like pulseaudio, esd etc. is not necessary.

Usage

OSS4 has several comandline tools and one gtk-GUI to configure the devices.

osstest

Maybe it just works, test all audio devices with the following command:

user $osstest

ossxmix

ossxmix is the graphical tool to configure devices:

Oss ossxmix.png

Troubleshooting

External Resources