Sound Blaster USB?

Alexander Leidinger Alexander at
Sat Feb 17 13:24:06 UTC 2007

Quoting Kazuhito HONDA <kazuhito at> (from Sat, 17 Feb  
2007 20:50:42 +0900 (JST)):

> Its cause is that FreeBSD sound system is unfit for USB sound systems.
> Some USB sound devices have several mute knobs.
> But FreeBSD sound system has one mute knob only.
> Thus FreeBSD can't control mute knobs of USB sound devices.

Did you had a look at the new OSS v4 API stuff? We can have more  
device specific mixers now. Unforunately no driver uses this yet, so  
no examples. But you can ask ryanb@ about them. He did implement this  
as part of the SoC last year. It allows to add all mixer devices, not  
only the hardcoded ones as specified by AC97. And I think it allows to  
have binary mixers (on/off), but I'm not sure about this part...

> `SB Live! 24-bit External' makes the mute knob on
> when none is plugged in `phones'.
> FreeBSD can't change the mute knob from on to off.
> Thus you can't get any sound.
> If something is plugged from beginning,
> the mute knob is off, and you can get some sounds.

Ah! This explains why I was able to get sound only sometimes. Now that  
something is always plugged in, I get sound always.


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