Name

snd_pcm_lib_preallocate_pages — pre-allocation for the given DMA type

Synopsis

int snd_pcm_lib_preallocate_pages (struct snd_pcm_substream * 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 dependent 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.