[alsa-devel] Distorted jackd output on Macbooks

[Takashi Iwai]

At Sat, 12 May 2012 00:27:34 +0200,
Adrian Knoth wrote:
> 
> On Tue, May 08, 2012 at 05:04:07PM +0200, Takashi Iwai wrote:
> 
> > > I've installed Linux on my spare MacBookPro and can report that JACKD is
> > > not to blame. aplay and jackd behave the same:
> > > 
> > >    FLOAT_LE is distorted
> > >    S32LE is fine
> > > 
> > > 
> > > So only FLOAT_LE is broken, S32LE and S24_3LE are fine.
> > 
> > OK, that's good to know.  I didn't know that the codec supports the
> > float.
> > 
> > I guess we can disable the support code for now like the patch below.
> > 
> > Could you check whether it works for you?
> > 
> > diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> > index 882bb3a..48c50dd 100644
> > --- a/sound/pci/hda/hda_codec.c
> > +++ b/sound/pci/hda/hda_codec.c
> > @@ -3781,11 +3781,13 @@ int snd_hda_query_supported_pcm(struct hda_codec *codec, hda_nid_t nid,
> >  					bps = 20;
> >  			}
> >  		}
> > +#if 0 /* FIXME: CS4206 doesn't work, which is the only codec supporting float */
> >  		if (streams & AC_SUPFMT_FLOAT32) {
> >  			formats |= SNDRV_PCM_FMTBIT_FLOAT_LE;
> >  			if (!bps)
> >  				bps = 32;
> >  		}
> > +#endif
> >  		if (streams == AC_SUPFMT_AC3) {
> >  			/* should be exclusive */
> >  			/* temporary hack: we have still no proper support
> 
> 
> Yep, this does the trick. Works.

OK, I applied the patch now.


thanks,

Takashi