From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lars-Peter Clausen <lars@metafoo.de>
Subject: Re: [RFC PATCH 3/4] ALSA: core: add report of max dma
 burst
Date: Fri, 10 Jul 2015 19:13:45 +0200
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To: Raymond Yau <superquad.vortex2@gmail.com>, Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
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On 07/10/2015 04:35 AM, Raymond Yau wrote:
[...]
> What is the usage of runtime->dma_bytes in
> snd_pcm_hw_constraints_complete() in core/pcm_native.c ?
>
> Was the usage similar to 128 bytes alignment ?
>
> /* FIXME: remove */
> if (runtime->dma_bytes) {
> err = snd_pcm_hw_constraint_minmax(runtime,
> SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 0, runtime->dma_bytes);
> if (err < 0)
> return err;
> }

The FIXME is probably correct. dma_bytes should always be 0 at that point. 
This is a freshly allocated runtime struct and dma_bytes only gets set once 
a buffer is allocated, which is done later on.

- Lars