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Date: Fri, 15 Jan 2016 10:38:24 -0800
From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Caleb Crome <caleb@crome.org>
Cc: Timur Tabi <timur@tabi.org>, Mark Brown <broonie@kernel.org>,
        Xiubo Li <Xiubo.Lee@gmail.com>, Liam Girdwood <lgirdwood@gmail.com>,
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        "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>
Subject: Re: [PATCH RFC 1/1] ASoC: fsl_ssi: Make fifo watermark and maxburst
 settings device tree options
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On Fri, Jan 15, 2016 at 09:03:28AM -0800, Caleb Crome wrote:

> If nobody objects, we can just set the value to 4 and be done with it.

I agree. And we may apply it only to i.MX platforms with DMA if
other platform owners feel comfortable with the previous settings.
 
> Another question:  is the watermark ever going to be different than
> maxburst?  Is there any reason to have them different?

The watermark is merely a threshold to trigger a DMA request. The
only relationship with the burst size is that each burst transfer
should not carry more data than the number of empty slots; FIFO
under/overflow occurs otherwise. So it's just more efficient and
safer to set an identical value to both of them. I don't think
it will cause functional problems to set TFWM to 4 and burst size
to 1 -- It just lets DMA operate in a single data transfer mode.