[pulseaudio-discuss] Sound Blaster Audigy (snd_ca0106 Creative Labs|SB Audigy LS): How to use the mixer?

Lennart Poettering lennart at poettering.net
Sun Aug 24 15:13:01 PDT 2008

On Sun, 24.08.08 22:54, Colin Guthrie (gmane at colin.guthr.ie) wrote:

> Hi,
> Just trying to help a user with a problem and it seems to be down to the 
> fact that his SB Audigy LS does not have a "Master" or "PCM" mixer control.
> I'm not too familiar with how things work but I thought that a Master or 
> PCM control was mandatory? If so is this an Alsa Bug? This is with 1.0.17.

Yes, Takashi said he wanted to make sure that all devices have at
least a Master vol control.

Instead of exporting three stereo controls for front, rear and
LFE/center, the card should export a single 6ch control with the name
"PCM" or "Master" 

It's especially fun to have a control like the following one, which
has Center on the Front Left and an LFE on the Front Right or
something like that. Very confusing ;-)

> Simple mixer control 'Analog Center/LFE',0
>   Capabilities: pvolume pswitch pswitch-joined
>   Playback channels: Front Left - Front Right
>   Limits: Playback 0 - 255
>   Mono:
>   Front Left: Playback 255 [100%] [12.00dB] [on]
>   Front Right: Playback 255 [100%] [12.00dB] [on]

The driver clearly needs fixing here.

(The reason for this strange way to export the mixer is probably that
the mute switch is joined for each of these pairs, i.e. you can mute
rear independently of front, but you cannot mute front-left
independently from front-right -- and ALSA knows only all-or-nothing
joined mute switches. But this should be fixed properly in the ALSA API)

Please bring this up on the ALSA ML.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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