From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolin Chen <nicoleotsuka@gmail.com>
Subject: Re: [PATCH] ASoC: fsl_ssi: Remove unneeded 'i2s-slave'
	property
Date: Fri, 19 Sep 2014 10:24:39 -0700
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To: Timur Tabi <timur@tabi.org>
Cc: "Fabio.Estevam@freescale.com" <Fabio.Estevam@freescale.com>, "Li.Xiubo@freescale.com" <Li.Xiubo@freescale.com>, "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, "broonie@kernel.org" <broonie@kernel.org>
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On Fri, Sep 19, 2014 at 07:51:46AM -0500, Timur Tabi wrote:
> Nicolin Chen wrote:
> >>You can't just redefine a property, because that breaks backwards
> >>>compatibility with older device trees or older kernels.
> 
> >Sorry, I'm not sure what's the problem here. It just drops i2s stuff
> >and leave AC97 part as we discussed. Why would old DTs be broken?
> >Is that possible for you to give me an example to understand the
> >point?
> 
> If you have an older kernel with a newer device tree (that doesn't have
> "i2s-mode"), the driver will fail to load because "i2s-mode" is missing.

I thought only the backward compatibility for DT is demanded.....
But I still don't get why people would use new DT without updating
kernel. It's pretty fair to use old DT with newer kernel because
they want bug-fix patches.

Thank you
Nicolin