SNDRV_PCM_INFO_MMAP - what do I need for it?

[Timur Tabi <timur@freescale.com>]

My 8610 ASoC driver has this:

static const struct snd_pcm_hardware fsl_dma_hardware = {

	.info   		= SNDRV_PCM_INFO_INTERLEAVED,

This means that MMAP is not enabled.

I understand what MMAP is, but not from an ALSA driver perspective.  If I change 
the above line to this:

	.info   		= SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 
SNDRV_PCM_INFO_MMAP_VALID,

what does ALSA do differently?  Do I need to define any new functions?  From an 
application perspective, what is different?

Also, does DMIX need MMAP support?

-- 
Timur Tabi
Linux kernel developer at Freescale