snd_pcm_lib_preallocate_pages — pre-allocation for the given DMA type
int snd_pcm_lib_preallocate_pages ( | struct snd_pcm_substream * | substream, |
| int | type, | |
| struct device * | data, | |
| size_t | size, | |
| size_t | max); |
substreamthe pcm substream instance
typeDMA type (SNDRV_DMA_TYPE_*)
dataDMA type dependant data
sizethe requested pre-allocation size in bytes
maxthe max. allowed pre-allocation size
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.