On Sun, May 10, 2015 at 08:33:20PM +0100, Russell King - ARM Linux wrote:

> My personal view is that where we're dealing with PCM audio, the driver
> needs to set these bits correctly as there is nothing in userspace to
> do this.  This provides an identical interface between each audio device
> which accepts PCM samples - whether it's a SPDIF or non-SPDIF based
> device.

> For non-audio data sent via an audio device, the AES bits need to be
> conveyed from userspace, and we should respect what userspace gives us.
> (If it's wrong, it's a userspace bug, and userspace should be fixed,
> rather than trying to work around the bug by patching the kernel.)

For what it's worth this is exactly what I'd be expecting to happen -
the kernel should do something by default and then let applications
override it if they so desire.