Takashi Iwai wrote on Sat, Nov 22, 2014 at 07:00:53PM +0100:
> At Sat, 22 Nov 2014 12:53:53 -0500,
> Martin Cracauer wrote:
> >
> > Takashi Iwai wrote on Sat, Nov 22, 2014 at 06:49:11PM +0100:
> > > At Sat, 22 Nov 2014 11:56:28 -0500,
> > > Martin Cracauer wrote:
> > > >
> > > > Takashi Iwai wrote on Sat, Nov 22, 2014 at 05:32:52PM +0100:
> > > > > At Fri, 21 Nov 2014 16:42:02 -0500,
> > > > > Martin Cracauer wrote:
> > > > > >
> > > > > > I have one Debian system with 1.0.25 and a Ubuntu system with 1.0.27
> > > > > > showing the same regression.
> > > > > >
> > > > > > Using
> > > > > > amixer -D hw:0 set Speaker [something]
> > > > > >
> > > > > > I used to be able to say 3db+ which would approximately do just that.
> > > > > >
> > > > > > As of recent updates the actual adjustment happening on 3db+ is kind
> > > > > > of random, way too small, sometimes even negative. It also does not
> > > > > > correspond in any way to amixer's own idea of what the absolute dbs
> > > > > > are:
> > > > > >
> > > > > > % amixer -D hw:0 set Speaker 14
> > > > > > Simple mixer control 'Speaker',0
> > > > > > Capabilities: pvolume pvolume-joined pswitch pswitch-joined
> > > > > > Playback channels: Mono
> > > > > > Limits: Playback 0 - 31
> > > > > > Mono: Playback 14 [45%] [-25.50dB] [on]
> > > > > > % amixer -D hw:0 set Speaker 3db+
> > > > > > Simple mixer control 'Speaker',0
> > > > > > Capabilities: pvolume pvolume-joined pswitch pswitch-joined
> > > > > > Playback channels: Mono
> > > > > > Limits: Playback 0 - 31
> > > > > > Mono: Playback 3 [10%] [-42.00dB] [on]
> > > > > >
> > > > > > I see that on 2 machines and on different kinda of soundcards.
> > > > > >
> > > > > > Things are so bad that "3db+" is actually lowering the volume now
> > > > > > depending on where you start.
> > > > >
> > > > > Use "3dB+" instead. It's case-sensitive.
> > > >
> > > > No, it's more broken (and it used to work with db all lowercase).
> > >
> > > Elaborate how "more broken".
> > >
> > > > I think the "db" in either casing makes it stop parsing and hence drop
> > > > the +, too, setting it to 3 absolute no matter whether you have +, -
> > > > or db or dB.
> > >
> > > No, read the source code:
> > >
> > > static int set_volume_simple(snd_mixer_elem_t *elem,
> > > snd_mixer_selem_channel_id_t chn,
> > > char **ptr, int dir)
> > > ....
> > > if (*p == '%') {
> > > percent = 1;
> > > p++;
> > > } else if (p[0] == 'd' && p[1] == 'B') {
> > > vol_type = VOL_DB;
> > > p += 2;
> > > scale = 100;
> > > } else
> > > vol_type = VOL_RAW;
> > >
> > > So it really needs to be "dB".
> >
> > Checking my CVS history I think you are right, I used dB.
> >
> > However, as of the updates that started this thread, it doesn't do
> > anything either way now, that's why I say it is more broken. At this
> > time "dB" in any case variant terminates parsing and "3dB+" is
> > interpreted as "3" (absolute), the + and - are lost.
>
> Are you sure that this behavior is seen with both 1.0.22 and 1.0.28?
> Please double-check with the right format "3dB+".
It is 1.0.25 and 1.0.28. I don't know about 1.0.22.
% amixer -D hw:0 set Master 100%
Simple mixer control 'Master',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 31 [100%] [on]
% amixer -D hw:0 set Master 3dB-
Simple mixer control 'Master',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 3 [10%] [on]
% amixer -D hw:0 set Master 3dB-
Simple mixer control 'Master',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 31
Mono: Playback 3 [10%] [on]
I am not convinced that we are looking at a problem with alsa-utils as
such here.
I found another machine, alsa utils 1.0.28, and there the above
sequence works as advertised. There might be something going on in
the libraries or even the drivers that makes the dB thing fail now.
I am sure it did work on the machine now running 1.0.25 before it
upgraded to it. It's in my CVS-controlled script that did work, on
that machine.
Martin
--
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