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

[Raymond Yau]

2011/8/16 Colin Guthrie <gmane at colin.guthr.ie>:
> 'Twas brillig, and Takashi Iwai at 09/08/11 13:40 did gyre and gimble:
>> At Tue, 09 Aug 2011 13:19:37 +0200,
>> Colin Guthrie wrote:
>>>
>>>>
>>>> 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


Revert this patch fix the problem for my logitech webcam
since dBmin and dBmax are still zero

ALSA endpoint.c:450: 2:3:1: add audio endpoint 0x86
dBMin 0 dBMax 0  min 0 max 1
control 1  UAC_FU_VOLUME 2
ALSA mixer.c:1186: [5] FU [Mic Capture Switch] ch = 1, val = 0/1/1
ALSA mixer.c:805: 5:2: cannot get min/max values for control 2 (id 5)
control 2  UAC_FU_VOLUME 2
dBmin 0 dBmax 0
ALSA mixer.c:1186: [5] FU [Mic Capture Volume] ch = 1, val = 0/1/1
ALSA mixer.c:805: 5:2: cannot get min/max values for control 2 (id 5)
usbcore: registered new interface driver snd-usb-audio
dBMin 1800 dBMax 3000  min 1200 max 1e00