[alsa-devel] maestro3 & es1988: mic range too low
tiwai at suse.de
Mon Aug 18 12:20:09 CEST 2008
At Sun, 17 Aug 2008 22:07:19 +0300,
> I'm having mic problems with snd_maestro3 and es1988 allegro hw. The
> laptop is HP OmniBook Xe3. The mic is way too silent (unusable) even
> with 20db boost option on. I found this seems to have been really
> common problem, but only one came with a fix  to the problem,
> enabling one more bit to volume control. Could someone please help me
> apply that fix to current alsa?
> I tried compiling 18.104.22.168 kernel and made the first change of the
> patch from mail  attachement . No change. The second part of
> patch I did not find anymore from the code. There are similar parts in
> ac97_patch.c. Any hint what should be added there?
Note that "Mic Playback Volume" controls only the volume of analog
playback. It doesn't change the recording level at all.
> The original patched code is somewhat outdated compared to modern
> one... But the reasoning for the original patch sounds reasonable. The
> mic volume is tunable, only at the very low range. I recall the laptop
> came with Win98, and there was no problem then with the sound -> not a
> HW problem. I have never got this laptop mic working with linux, so
> this is not anything that broke recently. I see there is
> check_volume_resolution function which tries to guess some of the
> register ranges, but maybe it get's it wrong with this HW.
Maybe, maybe not. You should check rather ac97 registers in
/proc/asound/card0/codec97#0/ac97#0-0+regs. If build with
CONFIG_SND_DEBUG=y, you can write to the register directly, too.
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