Re: Sound on KDE on Ultra 10 w/ CS4321

["Michael J. Saletnik" <michael@ties.org>]

On October 24, 2002 at 07:03, Daniel 'Doc' Sewell wrote:
 > I don't really understand the whole sound thing too well.  Is there a quick 
 > way to turn on OSS?  Do I have to recompile a kernel, or are there simply 
 > packages to apt-get?

This is actually not a Sparc-specific answer, but basically there is a
direct interface to audio, using such devices as /dev/audio, /dev/dsp,
/dev/mixer, etc. The specification for this interface is OSS. In
general, a program that wanted to output a sound sample would open
/dev/dsp, play the sound, and close.

This had a significant drawback - if something had the device already
open, such as XMMS playing music, other programs (one could claim
poorly-written) would either fail with an error message, or block.

Along came ESD. This daemon would handle mixing several streams into
the audio device simultaneously. People could hear their Gaim alert
sounds while listening to XMMS, and there was much rejoicing. Programs
could be linked directly against libesd (such as XMMS's esd output
device plugin), or you could use the esddsp wrapper which would cause
any program's attempt to open /dev/dsp to automagically be converted
to an esd stream.

Thing is, anything that was neither esd-aware nor run under esddsp
would still fail or block when trying to do audio, since the esd
daemon has the device open. This can cause all sorts of trouble: for
example, a stock RH7.3 x86 installation using Gnome and Galeon and
browsing to a web site with a Flash animation on it will hang Galeon
unless you've run it inside of esddsp. The same holds for forking off
a child RealPlayer. And even after you've done that once, if the Gnome
session management gets ahold of it, the next time you log in it will
start Galeon automatically without the esddsp.

The OSS drivers for various sound devices are all a part of the kernel
build configuration. If you're using prepackaged kernels, you may
already have modules. If you build your own, be sure to pick the right
one. And of course, check any audio applications that you use to
determine if they're going to try to use OSS directly or go through
ESD (ie, in XMMS check the active output plugin).

Hope this helps.

-- 
{michael}