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Via686a

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via82xx

This driver supports VIA's 82c686A, 686B and similar chips found in motherboards from many manufacturers. It's an AC97 chipset.

Mixer controls

As usual, ALSA provides a host of controls for the mixer on VIA's chipset. Because this chipset is used by many OEMs you may find some variation in the applicability of these instructions. If your board doesn't appear to actually have a phone connector, or multiple microphone sockets then those controls simply won't work, ALSA will mute them by default and you can ignore them.

  • Master - This controls the analog output level (for example to your headphones). Unmute and set to a comfortable level, try somewhere around 70-90%.
  • PCM - Controls the level from the ALSA PCM playback device. ie your MP3s, Game sounds etc. Unmute and set to a comfortable level, try 100% unless this causes distortion.
  • Line - Sound from the Line In connector (if any). Mute to reduce noise, unless you want to listen to something from Line In
  • CD - Sound from the CD or DVD drive, if there's one connected. Used only when the drive itself is playing audio. Mute when not in use.
  • Mic - Sound from the Mic In line. Once again mute when not in use.
  • Video/ Phone/ PC Speaker/ Aux - More input levels, unlikely to be connected. Mute.

This brings us to the capture controls, which affect recording only. Ordinarily there's no direct connection between what you hear, and what ALSA is recording (but you can change that as we'll see). You really need a software meter (VIA's chipset doesn't support a hardware meter) to know whether your levels are OK while recording, using video conferencing software etc. If your favourite application doesn't have such a mater, ask the author to consider adding one.

Like most consumer cards VIA's chipset can record from one source at a time. The choice of sources is: Line In, CD, Microphone, Video, Phone, Aux, and Mix. The last choice is special, it records more or less what's going to the Line Out, the result of the playback mixer controls. It's not affected by the Master levels control.

In order for anything to be recorded the appropriate recording source must be chosen and the Capture control turned on. You can also adjust the input gain for the recorded sound with the capture control. Often a relatively low level is best.

Module options

yast2 on SuSE has the following entries:

# modules.conf

options snd-via686 snd_ac97_clock=48000 snd_enable=1 snd_index=0
options snd snd_cards_limit=1 snd_major=116
# hlTL.zRM_II+f8jA:AC97 Audio Controller
alias snd-card-0 snd-via686

# YaST2: sound system dependent part
#
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-0-11 snd-mixer-oss
alias sound-service-0-12 snd-pcm-oss

Retrieved from "http://alsa.opensrc.org/Via686a"

Category: ALSA modules