Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
SYNOPSIS
int snd_pcm_lib_preallocate_pages (snd_pcm_substream_t * substream,
int type, struct device * data,
size_t size, size_t max);
ARGUMENTS
substream
the pcm substream instance
type DMA type (SNDRV_DMA_TYPE_*)
data DMA type dependant data
size the requested pre-allocation size in bytes
max the max. allowed pre-allocation size
DESCRIPTION
Do pre-allocation for the given DMA buffer type.
When substream->dma_buf_id is set, the function tries to look for the
reserved buffer, and the buffer is not freed but reserved at
destruction time. The dma_buf_id must be unique for all systems (in the
same DMA buffer type) e.g. using snd_dma_pci_buf_id.
Returns zero if successful, or a negative error code on failure.