[alsa-devel] Distorted jackd output on Macbooks

[Adrian Knoth]

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.


Cheers

-- 
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