[pulseaudio-tickets] [Bug 81777] Can't change optical-out volume on Terratec Aureon DualUSB

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=81777

--- Comment #3 from Tanu Kaskinen <tanuk at iki.fi> ---
(In reply to comment #2)
> Actually, PA does control the volume to a certain degree. Weird. It seems
> that by default, it chains a software controller and the "Speaker" mixer
> together. So from 0-33% I get software control, and from 33-100% I get the
> Speaker control (which naturally doesn't do anything on the optical output).

Yes, when dB information is available, PA applies software volume in addition
to hardware volume to make arbitrary volumes available, instead of limiting the
possible volumes to whatever steps the hardware happens to provide.

> PA seems to base that decision on the (wrong) dB values that are reported to
> it. I haven't quite figured out who to complain to about this issue tho.

The alsa-devel mailing list would be the right place (it's also good to CC the
maintainer of the USB audio driver or whatever component is responsible for the
dB values - unfortunately, I don't know who that would be or how to find out).
It should help your problem to get attention if you can also provide the
correct dB values. If you want to work on figuring out the right values, the
"decibel fix" feature in PulseAudio may be useful. You can specify the dB
values manually in /usr/share/pulseaudio/alsa-mixer/profile-sets/default.conf.
That file also contains some documentation about the DecibelFix configuration
section, but feel free to ask questions if there's something unclear.

> Interestingly, if I set ignore_dB=1 then PA falls back to software-mixing
> only. That actually seems like a simpler workaround ten yours, Tanu :P

That shouldn't happen... ignore_dB=1 should have the opposite effect: software
volume should get disabled for the device.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/pulseaudio-bugs/attachments/20140805/f418c4a3/attachment.html>