[alsa-devel] [PATCH] ASoC: s3c24xx platform: Fix s3c2410_dma_started called at wrong time

[Mark Brown]

On Thu, Aug 20, 2009 at 11:45:07PM +0800, Shine Liu wrote:

> > The callback doesn't need to be set up within the trigger function - if
> > it's done before the trigger functions are called then the DMA trigger
> > can call it.  Off the top of my head I'd expect it's possible to set it
> > up when the device is opened.

> Who call the DMA trigger? When? In any of the platform/cpu_dai trigger
> functions?

It's called ultimately by user space; within ASoC it's always called by
the core trigger function in the fixed order that it has.  The open()
callback would be a safe place to do the setup - that's called before
anything else.