Re: [PATCH v8 1/6] ALSA: pcm: add IEC958 channel status helper for hw_params - Russell King

From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Takashi Iwai <tiwai@suse.de>
Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
	peter.ujfalusi@ti.com, tomi.valkeinen@ti.com,
	arnaud.pouliquen@st.com, dri-devel@lists.freedesktop.org,
	liam.r.girdwood@linux.intel.com, tony@atomide.com,
	broonie@kernel.org, Jyri Sarha <jsarha@ti.com>,
	bcousson@baylibre.com, linux-omap@vger.kernel.org
Subject: Re: [PATCH v8 1/6] ALSA: pcm: add IEC958 channel status helper for hw_params
Date: Tue, 29 Mar 2016 18:23:12 +0100	[thread overview]
Message-ID: <20160329172312.GR5783@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <s5hzithhdfz.wl-tiwai@suse.de>

On Tue, Mar 29, 2016 at 10:54:08AM +0200, Takashi Iwai wrote:
> On Thu, 17 Mar 2016 13:22:29 +0100,
> Jyri Sarha wrote:
> > 
> > Add IEC958 channel status helper that gets the audio properties from
> > snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to
> > produce the channel status bits already in audio stream configuration
> > phase.
> > 
> > Signed-off-by: Jyri Sarha <jsarha@ti.com>
> 
> This patch looks almost good to me, but...
> 
> > @@ -71,6 +59,7 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
> >  			     IEC958_AES4_CON_MAX_WORDLEN_24;
> >  			break;
> >  		case 24:
> > +		case 32: /* Assume 24-bit width for 32-bit samples. */
> >  			ws = IEC958_AES4_CON_WORDLEN_24_20 |
> >  			     IEC958_AES4_CON_MAX_WORDLEN_24;
> >  			break;
> 
> ... this change is silently slipped in.  It should be mentioned in the
> changelog, or split to another patch, as this is basically an
> orthogonal change.

Does it even make sense - AES doesn't have support for 32-bit samples,
it can only ever truncate them down to 24-bit.

-- 
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