[alsa-devel] Bugs on aspire one A150

[Andreas Mohr]

Hi,

On Mon, Mar 16, 2009 at 01:09:50PM +0100, Takashi Iwai wrote:
> At Mon, 16 Mar 2009 13:03:12 +0100,
> Andreas Mohr wrote:
> > 
> > Hi,
> > 
> > On Sun, Mar 15, 2009 at 10:21:17AM +0100, Andreas Mohr wrote:
> > > Hi,
> > > 
> > > On Mon, Nov 24, 2008 at 03:35:10PM +0100, Takashi Iwai wrote:
> > > > At Sat, 22 Nov 2008 21:00:18 +0200,
> > > > Maxim Levitsky wrote:
> > > > > Finally, I found how to reproduce that bug,
> > > > > I mean to get normal volume on internal mic, I have to increase volume
> > > > > only on left or right channel.
> > > > > 
> > > > > So, this happens always, and _only_ when recording _mono_ sound from internal
> > > > > mic.
> > > > > 
> > > > > Since hardware doesn't support hardware mono input, tested with -D hw:0
> > > > > I suspect this to be alsa-lib bug, any ideas?
> > > > > Happens with arecord -D plughw:0 -c1 .
> > > > 
> > > > What does show with -v option?
> > > 
> > > OK, I could fully reproduce this now (sorry for the delay!).
> > > 
> > > Currently 2.6.28, u8.10, model acer-aspire, libasound2 1.0.17a-0ubuntu4,
> > > libasound2-plugins 1.0.17-0ubuntu5.
> > 
> > Same microphone behaviour on 2.6.29-rc8 (additionally remembered to enable
> > CONFIG_SND_HDA_HWDEP for further testing!), u9.04, model acer-aspire,
> > libasound2 1.0.18-1ubuntu7, libasound2-plugins 1.0.18-1ubuntu4
> > (yes, I've just done some monster upgrade).
> > 
> > Will try to eventually analyze things using your _HWDEP-related tools.
> 
> The question in the top priority is whether it's a kernel driver
> issue or alsa-lib converter issue.  Could you check whether the sounds
> recorded with -Dhw (and with matching rate, format, etc) have the same
> noise problem at first?

OK, tried arecord -v -D hw:0 -c1 test.wav, which ended with
arecord: set_params:961: Sample format non available
.

arecord -v -D hw:0 -c1 -f S16_LE test.wav then ended with
arecord: set_params:966: Channels count non available
thus completing it into a
arecord -v -D hw:0 -c2 -f S16_LE test.wav
worked.

Trying this line with plughw then worked (of course, since two channels
never has any problems).

Interestingly when using plughw there seems to be some LPF effect, since
with hw I get lots of white noise whereas with plughw the recorded sound
is dark (no higher-frequency components at all).

And audio is always being recorded properly no matter which Capture
sliders position.


To state it more clearly, both hw and plughw have no issues whatsoever
with -c2 -f S16_LE, any sliders position.
If I then switch to plughw:0 -c2 -f U8 (IOW change to U8 format),
no problems either. Trouble starts if I then change to -c1 and have
both channel sliders about equal (if they're not equal then I'm getting
audio returned properly).

> And, if it's about the alsa-lib conversion problem, we can reproduce
> without the hardware, e.g. via file plugin...

So, what to do?

> thanks,
> 
> Takashi

Thank You,

Andreas