[alsa-devel] [PATCH] ALSA: usb - Don't create "Speaker" mixer controls on headphones and headsets

David Henningsson david.henningsson at canonical.com
Mon Nov 26 16:26:02 CET 2012

On 11/26/2012 04:21 PM, Raymond Yau wrote:
> 2012-11-23 下午8:49 於 "David Henningsson"
> <david.henningsson at canonical.com
> <mailto:david.henningsson at canonical.com>> 寫道:
>  >
>  > A lot of headsets/headphones have a "Speaker" mixer control. This
> confuses
>  > PulseAudio to think it is a speaker instead of a headphone/headset.
>  > Therfore, we rename it to "Headphone".
>  >
>  > We determine if something is a headphone similar to how udev determines
>  > form factor (see 78-sound-card.rules).
> does it really fix the problem

It fixes a problem with a common class of Logitech stereo headsets.

> since there are
> 1) usb headsets which has "PCM" volume control
> 2) some usb headphone support 5.1

These devices are unlikely to be affected by the patch. If you have a 
problem with any of these devices, it's a different bug.

David Henningsson, Canonical Ltd.

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