[pulseaudio-discuss] Forcing sample rate, and mixer weirdness

[Tanu Kaskinen]

On Tue, 2013-05-21 at 18:15 +0200, Christian Iversen wrote:
> 2) This particular USB sound card has no hardware volume controls, 
> except physical tuning knobs. When I use kmix to turn the volume 
> up/down, it indeed works, and as far as I can tell, it communicates with 
> PA to do so. (and it works just fine).
> 
> However, the first time I play a source after PA has started, the PA 
> volume is at 100%. Which means that if I forget to turn the volume down 
> in kmix, my USB device becomes a Sound Blaster (mehehe..).
> 
> Interestingly, kmix remembers that the volume is supposed to be around 
> ~30%, so when I turn it one step down (I have a hotkey for that), it 
> goes to ~25% immediately, instead of just the second-highest step. I 
> guess this is because kmix remembers where the volume was supposed to be 
> at, and not because of PA's as such.
> 
> However, remembering and restoring the volume between reboots works fine 
> with all other sound cards, which have hardware mixers. What could be 
> causing these problems?

Perhaps this? https://bugs.freedesktop.org/show_bug.cgi?id=55262

> Who is responsible for restoring volume in this 
> case - is it kmix, PA, or a combination?

PA is responsible for all volume restoring.

> Is this happening because the restore code does not want to enforce 
> software volume control?

No, the restoring code doesn't distinguish between hw ans sw volume.

-- 
Tanu