From mboxrd@z Thu Jan  1 00:00:00 1970
From: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Subject: Re: [RFC 1/4] ASoC: topology: Add topology UAPI header.
Date: Wed, 22 Apr 2015 12:30:37 +0100
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To: Mark Brown <broonie@kernel.org>
Cc: Takashi Iwai <tiwai@suse.de>, "Koul, Vinod" <vinod.koul@intel.com>, "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, Lars-Peter Clausen <lars@metafoo.de>
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On Wed, 2015-04-22 at 12:24 +0100, Mark Brown wrote:
> On Tue, Apr 21, 2015 at 06:46:28PM +0200, Lars-Peter Clausen wrote:
> > On 04/21/2015 06:35 PM, Mark Brown wrote:
> 
> > >The trouble with the ABI version information is that it tells new
> > >kernels how to handle old tables but old kernels will have no idea what
> > >to do with new firmwares.
> 
> > What I did for the SigmaDSP firmware format (which can hopefully be
> > superseded by this) is to have a header which a block type and the block
> > length for each block for exactly this reason. It allows fully backward and
> > forward compatibility between kernel versions and does not require a change
> > in the ABI each time a new type of block is added. It also keeps the parser
> > simple since it does not have to know the size and also makes support for
> > vendor blocks quite easy, since the processing of those can be offloaded to
> > some vendor callbacks without the core having to be informed what the
> > content or size of those vendor blocks is.
> 
> Yes, that's what the ex-Wolfson stuff does too (it also has ABI
> versioning but most things shouldn't need it).

Ok, I'll add in the block length for V2. Travelling atm so V2 will
probably arrive sometime next week.

Liam