VIA 声卡配置

Debian下VIA 82XX声卡的声音太低的解决方案：

amixer set 'VIA DXS',0 100%
amixer set 'VIA DXS',1 100%
amixer set 'VIA DXS',2 100%
amixer set 'VIA DXS',3 100%

---

Install ALSA

The provides audio and MIDI functionality to the Linux operating system.

The Gentoo is a good documentation about this installation. The provides specific information about ALSA on the Via EPIA mainboards.

Prepare

Remove previous sound drivers:

cd /usr/src/linux
cp .config ~/
make mrproper
mv ~/.config .
make menuconfig
    

In the menus, select Sound ---> Sound Card Support as Module (M) and deselect all other sound drivers.

make dep clean
make modules modules_install
    

Specify your sound card in /etc/make.conf. Check for your card in the . For an Epia-M motherboard, for example, insert the line

ALSA_CARDS="via82xx"
    

You might as well pre-fetch the installation files with a emerge -f ... or a wget ...

Install

Install ALSA

emerge alsa-driver
emerge alsa-utils
    

Edit the ALSA configuration in /etc/modules.d/alsa. For an Epia-M motherboard, for example, make sure you have:

# ALSA portion 
alias char-major-116 snd 
alias snd-card-0 snd-via82xx 
options snd-via82xx dxs_support=3

# OSS/Free portion 
alias char-major-14 soundcore 
alias sound-slot-0 snd-card-0 

alias sound-service-0-0 snd-mixer-oss 
alias sound-service-0-1 snd-seq-oss 
alias sound-service-0-3 snd-pcm-oss 
alias sound-service-0-8 snd-seq-oss 
alias sound-service-0-12 snd-pcm-oss 

alias /dev/mixer snd-mixer-oss 
alias /dev/dsp snd-pcm-oss 
alias /dev/midi snd-seq-oss

options snd cards_limit=1
    

Start ALSA and add it at boot time

modules-update
/etc/init.d/alsasound start
rc-update add alsasound boot
    

Unmute the mixer, command line interface:

amixer set Master 100% unmute
amixer set PCM 100% unmute
aplay $KDEDIR/share/sounds/pop.wav
    

or graphic interface ( Press 'M' to unmute, Up and Down to adjust the volume levels, 'Esc' to exit):

alsamixer
    

and test it (if KDE is installed)

aplay $KDEDIR/share/sounds/pop.wav
    

On EPIA mother boards, the sound output must be sampled at 48 kHz. To be sure this is done, create the file ~/.asoundrc with :

pcm.via82xx {
  type plug
  slave {
    pcm "hw:0,0"
    rate 48000
  }
}
ctl.via82xx {
  type hw
  card 0
}
    

I have been told that this 48 kHz sampling is not mandatory and that the following settings also work fine:

options snd-via82xx dxs_support=1
    

or

options snd-via82xx dxs_support=4
    

Here an information about dxs support:
• 0: (default value) no DXS support, used for VIA8233A chips.
• 1: enable full DXS support (at any supported sample rate).
• 2: no DXS support: the hardware mixing ability of the chip is not used.
• 3: DXS support at 48000 Hz only.
• 4: DXS support at any supported sample rate with the codec set to 48000 Hz.

Using ALSA

Tools

With this, you have the following utilities:

• amixer: the command-line control of the mixer,
• aplay: a command-line sound player, plays voc, wav, raw or au files.
• arecord: a command-line sound recorder.

KDE

Setup KDE to use ALSA for the sounds:

-> Control Center Modules
  -> Sound & Multimedia
    -> Sound system
      -> Hardware
        -> Select the audio device: Advanced Linux Sound Architecture
    

After installing KDE on an EPIA motherboard, the sound is muted on startup. This is due to the last 4 mixer controls to be set to zero. These controls can be set to 100% with the following commands:

amixer set 'VIA DXS',0 100%
amixer set 'VIA DXS',1 100%
amixer set 'VIA DXS',2 100%
amixer set 'VIA DXS',3 100%
    

This initial setup can be automated by creating a alsaInit.sh file in ~/.kde/Autosrtart (with "execute" rights):

#!/bin/bash
amixer set 'VIA DXS',0 100%
amixer set 'VIA DXS',1 100%
amixer set 'VIA DXS',2 100%
amixer set 'VIA DXS',3 100%
    

I have been told that with other distributions or ALSA versions, there were further mute problems which can be solved by adding:

amixer set 'IEC958 Capture Monitor' muted
amixer set 'PCM' unmuted
    

On a PC with an ISA card and KDE installed, I had trouble playing tracks with alsaplayer. I worked around it with the following command:

$ artsd -a alsa
    

As an alternative, I could remove the autosuspend mode in the sound system control center module.