LTSP | LTSP4.2 Client Sound

Step 1 - Switch on sound

Firstly, you need to switch sound on for the clients.

# File: /opt/ltsp/i386/etc/lts.conf
# enable sound by default
SOUND                   = Y
# choose either esd or nasd to be the default (esd only on x86_64)
SOUND_DAEMON            = esd
VOLUME                  = 100 # Speaker & WAVE volume pecentage
MIC_VOLUME              = 100 # Microphone volume
CD_VOLUME               = 75  # CD Audio volume

Step 2 - Identify soundcard

To determine what Soundcard is installed in your PC, add the line:

# File: /opt/ltsp/i386/etc/lts.conf
SCREEN_02          = shell

Then enter after rebooting, enter shell by typing Ctrl+Alt+F2. In the shell, to show any PCI Soundcards, type:

# lspci -v | more

Look for a device stating “audio” and make a note of the salient details. For example my test PC has the following details:

Intel 82801EB/ER AC97 IRQ5 IO Port d400 @ 256k and d800 @ 64k.

Step 3 - Check

Check the following website - you might strike lucky!

Step 4 - Determine appropriate driver

To decide the appropriate driver to use, typing the following command on the server or functioning client, will give you a list of available drivers:

$ find /opt/ltsp/i386/lib/modules/ | grep snd

Step 5 - Identify sound module with Knoppix

Boot the client with Knoppix and from a terminal window type “lsmod” to identify the sound module.

Step 6 - Trial and error

At this point it’s probably worth removing, or commenting out the sound options, so that the client boots without any sound modules loaded. Once booted key Ctrl+Alt+F2.

Unless you have a good knowledge of sound drives, this is going to be a little bit of trial and error - remember Google is your friend. In this instance I Googled for “LTSP Intel 82801EB” and found a page detailing the following:

Intel Corp. 82801EB/ER (ICH5/ICH5R) AC’97 Audio Controller

lsmod grep -i intel

snd_intel8x0m 20036 1

I compared this with the output from Step 4 and decided the best match was “snd-intel8x0”.

# modprobe snd-intel8x0

The command responded with some clean output. I therefore added the following to LTS.CONF:

SMODULE_01         = "snd-intel8x0"

And success!

A common Soundblaster compatible card is:

# File: /opt/ltsp/i386/etc/lts.conf
SMODULE_01 = "sb io=0x220 irq=5 dma=1"

Other issues

Soundcard okay but no sound

If you are confident that the soundcard is being identified correctly and there are no errors on boot-up, then perhaps the volume is muted. The only volume controls at our disposal are:

VOLUME                  = 100 # Speaker & WAVE volume pecentage
MIC_VOLUME              = 100 # Microphone volume
CD_VOLUME               = 75  # CD Audio volume

However from a client shell you can try the following:

$ cd /share/sounds/alsa
$ esdplay Noise.wav
$ amixer scontrols              # Take a note of them
$ amixer sget Front             # To view each control
$ amixer sset Front 75% unmute   # To set a control called Front to 75% volume

snd-hda-intel issues

Oh, so may issues. Try each of the following in lts.conf:

Google for ALSA-Configuration.txt and review section on snd-hda-intel.

SMODULE_01              = "snd-hda-intel model=auto"
SMODULE_01              = "snd-hda-intel model=3stack"
SMODULE_01              = "snd-hda-intel model=3stack-dig"
SMODULE_01              = "snd-hda-intel index=0 probe_mask=3 position_fix=3"
SMODULE_01              = "snd-hda-intel position_fix=1 model=3stack"

Sound muted

All working but sound muted. Save this script as “unmute” in /opt/ltsp/i386/etc/rc.d:

# Copyright Gideon Romm, Symbio Technologies
# Released under GPLv2
# This is a script to set up certain things 
# that are not already setup in an SBA environment
# Specifically:
#   1. restore sound levels

# Set up local environment
if [ -f /etc/lts.conf ]; then
    eval `getltscfg -a`

# Set up sound
if [ -n "$VOLUME" ]; then
    amixer sset Master,0 ${VOLUME}% unmute 2>/dev/null
    amixer sset 'Master Digital',0 ${VOLUME}% unmute 2>/dev/null
    amixer sset Headphone,0 ${HEADPHONE_VOLUME:-$VOLUME}% unmute 2>/dev/null

if [ -n "$PCM_VOLUME" ]; then
    amixer sset PCM,0 ${PCM_VOLUME}% unmute 2>/dev/null

if [ -n "$MIC_VOLUME" ]; then
    amixer sset Mic,0 ${MIC_VOLUME}% unmute cap 2>/dev/null

if [ -n "$CD_VOLUME" ]; then
    amixer sset CD,0 ${CD_VOLUME}% unmute 2>/dev/null

if [ -n "$FRONT_VOLUME" ]; then
    amixer sset Front,0 ${FRONT_VOLUME}% unmute 2>/dev/null

Then add the following line to LTS.conf:

RCFILE_01          = unmute

This unmute script also adds the functionality of FRONT_VOLUME, which may be set in LTS.CONF:

FRONT_VOLUME       = 100

The script could be easily modified to enable other volume controls is required.

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