Re: Lost dB volumes on USB headset between 2.6.38 and 3.0

[David Henningsson <david.henningsson@canonical.com>]

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On 2011-08-09 12:39, Clemens Ladisch wrote:
> David Henningsson wrote:
>> Hmm, I and Colin Guthrie have found a regression between kernels 2.6.38
>> and 3.0.
>>
>> When running "amixer -D hw:handset" for this device under 2.6.38, the
>> attached file is returned. Under 3.0, the dB information is missing.
>> This can't be intentional, can it?
>
> There are patches that might have introduced bugs, but these two patches
> do remove dB information intentionally:
>
> ALSA: usb-audio - Don't expose broken dB ranges:
> http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=59bb7f0eebe6
> ALSA: usb-audio - Add volume range check and warn if it too big:
> http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=80acefff3bc7
>
> Are there any messages in the system log when loading the driver?
> What are the controls' dB ranges (see "amixer contents")?

I'm attaching "amixer contents" from 2.6.38. Colin will attach some 
interesting dmesg output from 3.0 shortly.

-- 
David Henningsson
http://launchpad.net/~diwic

[-- Attachment #2: amixercontents.log --]
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numid=13,iface=MIXER,name='PCM Capture Source'
  ; type=ENUMERATED,access=rw------,values=1,items=3
  ; Item #0 'Mic'
  ; Item #1 'Line'
  ; Item #2 'IEC958 In'
  : values=0
numid=3,iface=MIXER,name='Line Playback Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off
numid=4,iface=MIXER,name='Line Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=0,0
  | dBminmax-min=0.00dB,max=47.81dB
numid=10,iface=MIXER,name='Line Capture Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on
numid=11,iface=MIXER,name='Line Capture Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=128,step=0
  : values=1,1
  | dBminmax-min=0.18dB,max=23.81dB
numid=1,iface=MIXER,name='Mic Playback Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off
numid=2,iface=MIXER,name='Mic Playback Volume'
  ; type=INTEGER,access=rw---R--,values=1,min=0,max=255,step=0
  : values=191
  | dBminmax-min=0.00dB,max=47.81dB
numid=7,iface=MIXER,name='Mic Capture Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off
numid=8,iface=MIXER,name='Mic Capture Volume'
  ; type=INTEGER,access=rw---R--,values=1,min=0,max=128,step=0
  : values=0
  | dBminmax-min=0.18dB,max=23.81dB
numid=12,iface=MIXER,name='IEC958 In Capture Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on
numid=9,iface=MIXER,name='Auto Gain Control'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off
numid=5,iface=MIXER,name='Speaker Playback Switch'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on
numid=6,iface=MIXER,name='Speaker Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=148,148
  | dBminmax-min=-47.87dB,max=0.06dB

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