2011/3/10 Alexey Fisher bug-track@fisher-privat.net
One more affected devices: Logitech Webcam C600 (046d:0808)
Volume range before quirk is 6400, after (also real) is 16.
Signed-off-by: Alexey Fisher bug-track@fisher-privat.net
sound/usb/mixer.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index eba8ae8..c549522 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1122,6 +1122,7 @@ static void build_feature_ctl(struct mixer_build *state, void *raw_desc, } break;
case USB_ID(0x046d, 0x0808): case USB_ID(0x046d, 0x0809): case USB_ID(0x046d, 0x0991): /* Most audio usb devices lie about volume resolution.-- 1.7.1
It is because each step of usb audio is 1/256dB , so 384 step is 1.5dB
Is there any way to verify the resolution is 1.5dB ?
since alsamixertest does not check the capture volume (only check the playback volume)
And mindB +18dB and maxdB +30dB , It can still record sound using audacity at +18dB , so it seem break the pulseaudio developer 's assumption that 0% is -infinite dB
state.U0x46d0x992 { control.1 { iface MIXER name 'Mic Capture Switch' value false comment { access 'read write' type BOOLEAN count 1 } } control.2 { iface MIXER name 'Mic Capture Volume' value 3072 comment { access 'read write' type INTEGER count 1 range '0 - 3072' dbmin 1800 dbmax 3000 dbvalue.0 3000 } } }