Question about your DSP topic branch - hw param fix up query

From: Patrick Lai <plai@codeaurora.org>
To: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	Mark <broonie@opensource.wolfsonmicro.com>
Subject: Question about your DSP topic branch - hw param fix up query
Date: Thu, 31 Mar 2011 10:45:23 -0700	[thread overview]
Message-ID: <4D94BDB3.4050903@codeaurora.org> (raw)
In-Reply-To: <1301512193.3375.31.camel@odin>

Change subject

> static int dmic_be_hw_params_fixup(struct snd_soc_pcm_runtime *rtd,
> 			struct snd_pcm_hw_params *params)
> {
> 	struct snd_interval *rate = hw_param_interval(params,
> 			SNDRV_PCM_HW_PARAM_RATE);
>
> 	/* The ABE will covert the FE rate to 96k */
> 	rate->min = rate->max = 96000;
>
> 	snd_mask_set(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT -
> 	                            SNDRV_PCM_HW_PARAM_FIRST_MASK],
> 	                            SNDRV_PCM_FORMAT_S32_LE);
> 	return 0;
> }
Liam,

For sample rate conversion case, supplying back-end hw_params_fixup 
function would work. However, I am looking for run-time configuration of 
back-end channel mode. For scenario of multi-channel microphone input, I 
need to have a mean to specify channel mode of back-end depending on 
algorithm running on DSP while front-end channel mode is mono. Is there 
a hook in the framework to do that?

Thanks
Patrick

>
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