[alsa-devel] Lost dB volumes on USB headset between 2.6.38 and 3.0

David Henningsson david.henningsson at canonical.com
Tue Aug 9 13:19:09 CEST 2011

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
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