[alsa-devel] Bugs on aspire one A150

[Andreas Mohr]

Hi,

On Mon, Mar 16, 2009 at 03:18:20PM +0100, Takashi Iwai wrote:
> At Mon, 16 Mar 2009 14:30:01 +0100,
> Andreas Mohr wrote:
> > 
> > Hi,
> > 
> > On Mon, Mar 16, 2009 at 01:09:50PM +0100, Takashi Iwai wrote:
> > > 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).
> 
> So, the following is also problematic
> 
> 	% arecord -fdat -c1 -Dplughw ng.wav
> 
> while the below works?
> 
> 	% arecord -fdat -Dhw good.wav

Indeed, the above has problems with problematic slider positions whereas
the below never has.

> 
> > > 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?
> 
> Does the conversion by sox from good.wav to a mono-channel file work?

I assume I should be using
sox good.wav -c1 good1.wav
?

If so, yes, this works, audio is there.


Side note: I've got HDA power management activated (with some bad
effects - no sound at all on entire first playback after idle),
but this shouldn't matter here.

Andreas