#!/bin/sh
# Load the mixer settings and OSS compatibility for ALSA.
# (the Advanced Linux Sound Architecture)

# A function to try setting some sane defaults for ALSA:
set_alsa_defaults() {
  local cards=`cat /proc/asound/cards | \
    sed 's/^\([0-9][0-9]*\) .*/\1/;s/^ .*//;'`
  for card in $cards; do
    for output in 'Master' 'PCM' 'Line' 'CD' 'PC Speaker'; do
      /usr/bin/amixer --card $card sset $output unmute 77% &>/dev/null
    done
    /usr/bin/amixer --card $card sset 'Mic' mute capture 77% &>/dev/null
    /usr/sbin/alsactl store $card
  done
}

# A function to load the ALSA mixer settings:
load_alsa_mixer() {
  if [ -r /etc/asound.state ]; then
    echo "Loading ALSA mixer settings:  /usr/sbin/alsactl restore"
    /usr/sbin/alsactl restore
  else
    set_alsa_defaults
    echo "ALSA warning:  No mixer settings were found in /etc/asound.state."
    echo "Common devices have now been set to 77% and unmuted.  You may still"
    echo "wish to adjust the sound levels with alsamixer."
  fi
}

# A function to generate the names for the ALSA mixer devices:
create_alsa_names() {
  if [ ! -r /etc/asound.names ]; then
    echo "Generating device names for ALSA mixer devices."
    /usr/sbin/alsactl names
  fi
}

# A function to load the ALSA OSS compat modules:
load_alsa_oss_modules() {
  if ! cat /proc/modules | grep -wq snd-pcm-oss ; then
    if ! cat /proc/modules | grep -wq snd_pcm_oss ; then
      echo "Loading OSS compatibility modules for ALSA."
      modprobe snd-pcm-oss
      modprobe snd-mixer-oss
    fi
  fi
}

# If hotplug or something else has loaded the ALSA modules, then
# simply load the mixer settings and make sure the OSS compat
# modules are loaded:
if [ -d /proc/asound ]; then
  create_alsa_names
  load_alsa_mixer
  load_alsa_oss_modules
else
  # If there are ALSA modules defined in /etc/modules.conf, but
  # ALSA is not yet loaded, then load the modules now:
  DRIVERS=`modprobe -c | grep -E "^[[:space:]]*alias[[:space:]]+snd-card-[[:digit:]]" | awk '{ print $3 }'`
  if [ ! "$DRIVERS" = "" ]; then
    echo "Loading ALSA kernel modules."
    for module in $DRIVERS; do
      modprobe $module
    done
  fi
  # If ALSA is now up, then load the mixer settings and OSS modules:
  if [ -d /proc/asound ]; then
    create_alsa_names
    load_alsa_mixer
    load_alsa_oss_modules
  fi
fi