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From: js@sig21.net (Johannes Stezenbach)
To: linux-arm-kernel@lists.infradead.org
Subject: [alsa-devel] [PATCH] ARM: pxa: add support for Raumfeld DDX
Date: Wed, 16 Nov 2011 16:07:22 +0100	[thread overview]
Message-ID: <20111116150722.GA15580@sig21.net> (raw)
In-Reply-To: <4EC3B30F.60403@gmail.com>

On Wed, Nov 16, 2011 at 01:56:47PM +0100, Daniel Mack wrote:
> On 11/15/2011 03:13 PM, Mark Brown wrote:
> > On Mon, Nov 07, 2011 at 11:26:02AM +0100, Daniel Mack wrote:
> > 
> >> +	/* PXA DMA cannot do zero extend for 24bit samples,
> >> +	* thus only 16bit (two samples packet into 32bit word)
> >> +	* or 32bit samples are possible
> >> +	*/
> >> +	snd_pcm_hw_constraint_mask64(substream->runtime,
> >> +				    SNDRV_PCM_HW_PARAM_FORMAT,
> >> +				    SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_S16_BE |
> >> +				    SNDRV_PCM_FMTBIT_S32_LE  | SNDRV_PCM_FMTBIT_S32_BE);
> > 
> > If the PXA DMA controller can't do 24 bit audio it should be imposing
> > this constraint.
> 
> Right. Will fix this in the CPU DAI.

IIRC the PXA can handle 24bit audio, and the STA32x can handle it, too.
However due to constraints in the clock ratios on the Raumfeld board
this mode cannot be used.  Thus this constraint is in sound/soc/pxa/raumfeld.c.

Does that make sense?  It's been a while since I worked on this code,
maybe I misremember.  And I failed to mention it in the code comment :-(


Johannes

  parent reply	other threads:[~2011-11-16 15:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-07 10:26 [PATCH] ARM: pxa: add support for Raumfeld DDX Daniel Mack
2011-11-15 14:13 ` Mark Brown
2011-11-16 12:56   ` Daniel Mack
2011-11-16 13:19     ` Mark Brown
2011-11-16 14:06       ` Daniel Mack
2011-11-16 14:11         ` Mark Brown
2011-11-16 14:19           ` Daniel Mack
2011-11-16 15:07     ` Johannes Stezenbach [this message]
2011-11-16 16:07       ` [alsa-devel] " Mark Brown

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