Re: [PATCH v7 2/2] ASoC: fsl: Add S/PDIF machine driver

On Mon, Aug 19, 2013 at 12:31:21PM +0100, Mark Rutland wrote:

On Mon, Aug 19, 2013 at 11:52:01AM +0100, Mark Brown wrote:

quoted

This is intended to allow userspace to distinguish between systems that
are electrically identical but physically distinct, for example when
multiple systems are derived from the same reference design.

I see. Surely if there's some meaning imparted to userspace by the model
name, there's a contract there that we should document (the set of valid
model names and what they correspond to)?

In theory I guess.  In practice I doubt many people will bother and I'd
expect zero productive result from those that do.

I'm not sure I understand why userspace needs to know what the system is
if we've adequately described how it's wired and what its capabilities
are. However, I'm not at all familiar with the way we handle audio, so
please forgive my naivety there :)

The physical form of the system can have a substantial impact on how
people want to configure it at runtime even if there is no software
visible difference.  Coefficients can be chosen to work with plastics,
or volumes adjusted for expected user positioning with respect to the
hardware for example.