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

Clemens Ladisch clemens at ladisch.de
Tue Aug 9 12:39:57 CEST 2011

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:
ALSA: usb-audio - Add volume range check and warn if it too big:

Are there any messages in the system log when loading the driver?
What are the controls' dB ranges (see "amixer contents")?


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